Stephen Kosmin specialises in administrative and public law, procurement law, financial services, and information and data protection law. He is ranked by both Chambers and Partners and the Legal 500 in each of those areas of practice. Stephen is additionally ranked by the Legal 500 in local government law and by Chambers and Partners in civil liberties and human rights. In August 2023, Stephen was appointed to the Attorney General’s A Panel.

Stephen has wide-ranging trial and appellate court experience, particularly in high-value and multi-party disputes. Recently, Stephen has appeared:

  • in the Supreme Court in R (Bancoult) v Secretary of State for Foreign and Commonwealth Affairs (No 3), acting for the appellant; in Cox v Ministry of Justice, acting for the respondent; and in Independent Workers Union of Great Britain v Central Arbitration Committee and Roofoods Ltd (t/a Deliveroo), acting for the intervener;
  • in the Court of Appeal in Secretary of State for Work and Pensions v AT (European Union law, Universal Credit), acting for the Secretary of State; in Cobalt Data Centre 2 LLP v HMRC, acting for HMRC; in R (Bridges) v Chief Constable of South Wales, acting for the Surveillance Camera Commissioner; in Kimathi v Foreign and Commonwealth Office, acting for the Foreign and Commonwealth Office; and in R (Tesfay) v Secretary of State for the Home Department, acting for the Home Secretary;
  • in the Administrative Court in public law cases, including R (Charles Street Securities Europe LLP) v Financial Ombudsman ServiceR (Get Real Marketing Company Ltd) v Culture Recovery BoardR (Police Superintendents’ Association) v HM Treasury; and R (Enterprise Managed Service Ltd) v Secretary of State for Housing, Communities and Local Government;
  • in the Technology and Construction Court in procurement claims, including James Waste Management LLP v Essex County CouncilAlstom Transport UK Ltd v Network Rail Infrastructure LtdR (Good Law Project) v Prime MinisterAltiatech Ltd v Birmingham City Council; and Kenson Contractors (Benington) Ltd v Haringey Ltd;
  • in the King’s Bench Division in Prismall v Google UK LtdSeadrill Ghana Operations v Tullow Ghana Ltd; and Berkeley Burke Sipp Administration v Financial Ombudsman Service;
  • in the Upper Tribunal and First-tier Tribunal in tax disputes and information law cases, including Ticketmaster UK Ltd v Information CommissionerOfqual v Information CommissionerMaurizi v Information Commissioner; and Myhill v General Medical Council.

Stephen also has considerable experience and expertise of public international law, arbitral proceedings, and negotiations.

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  • Quotation symbolHe had everything at his fingertips. He is a polished all-round advocate. I can’t think of any weaknesses. He stood out as someone who has ability beyond their years or call.

    Quotation symbolChambers & Partners
  • Quotation symbolFirst-class attention to detail, and impressive all-round skills. As well as knowing the law inside out, Stephen is a confident and impressive advocate. Judges listen.

    Quotation symbolLegal 500
  • Quotation symbolStephen combines unusual thoroughness with exceptional legal creativity. He is remarkably clever. His pleadings are fantastic. And if there is a solution to a problem to be found he will find it.

    Quotation symbolLegal 500

Expertise

ToggleAdministrative & Public

Stephen has a broad practice in public law. He advises, and appears on behalf of, both claimants and public authorities of different kinds. In August 2023, he was appointed to the Attorney General’s A Panel.

Stephen is highly regarded in public law. He has been ranked by Chambers and Partners and the Legal 500 in Administrative and Public law for a number of years. He is also ranked both by Chambers and Partners in Civil Liberties and Human Rights and by Legal 500 in Local Government Law. In 2022, he was a shortlisted as Government and Third Sector Junior of the Year by the Legal 500.

Stephen appears regularly in judicial review proceedings in the Supreme Court, Court of Appeal, and High Court. Additionally, he is often instructed in the Upper Tribunal. Stephen has a developed knowledge of costs in public law proceedings.

Stephen acts both for claimants and defendants in public law proceedings, as well as undertaking advisory work. Stephen has recently advised the following clients:

  • Government departments.
  • Local authorities.
  • NHS trusts.
  • Network Rail.
  • Financial regulators and financial dispute resolution schemes, including the Bank of England, Serious Fraud Office, Financial Services Compensation Scheme, and Financial Ombudsman Service.
  • Professional regulators, including the Health and Care Professions Council, the General Medical Council, and the Information Commissioner.
  • Educational institutions.
  • Private clients and representative organisations.

Stephen taught Administrative Law and Constitutional EU Law at university and has since advised frequently on EU law, the legal consequences of Brexit, and associated matters.

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  • Stephen drills right into the detail. He is very creative, has amazing research skills and pushes the boundaries of things.

    Chambers & Partners
  • It is not a question of if but when he takes silk. Stephen is supremely clever and never looks out of place when his year of call is much less than everyone on the team.

    Chambers & Partners
  • Stephen is an exceptional barrister with a brilliant attention to detail. He is excellent on technical legal issues. He is one of our go-to barristers for public sector work.

    Chambers & Partners

Download Public CV

ToggleProcurement

Stephen specialises in procurement disputes. He has been ranked by both Chambers and Partners and the Legal 500 in Procurement Law for a number of years. In 2022, he was a shortlisted as Government and Third Sector Junior of the Year by the Legal 500.

As well as being instructed regularly in procurement litigation, Stephen also advises on procurement processes and challenges. He acts for claimants, public authorities, and affected bidders.

Stephen has recently advised on:

  • The abandonment of procurement exercises.
  • Re-procurements.
  • Modifications of procured contracts during their terms.
  • Sequential and related procurement exercises.
  • The proper interpretation of terms of procurement documentation.
  • The process of evaluating tenders, including normalisation.
  • Abnormally low tenders.
  • The relationship of the laws of state aid and procurement.
  • Issues arising from Faraday Development Ltd v West Berkshire Council [2019] PTSR 1346.
  • During the Coronavirus pandemic, Stephen was instructed to advise on the interpretation of tendered contracts, including their force majeure clauses and the doctrine of frustration. Stephen has also advised on the effect of various Coronavirus Regulations.

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  • Stephen Kosmin is outstanding and user-friendly.

    Chambers & Partners
  • Stephen Kosmin is an excellent barrister who is meticulous and thorough.

    Chambers & Partners
  • Stephen Kosmin is calm under pressure and can be trusted with a really heavy case.

    Chambers & Partners

Download Procurement & State Aid CV

ToggleFinancial Services

Stephen is very experienced in financial regulation and financial services law. He specialises in disputes concerning the jurisdiction and decision-making of financial regulators and dispute resolution schemes. In particular, he regularly advises on the liability of SIPP operators and appointed representatives, tax avoidance schemes, collective investment schemes, and the mis-selling of financial products.

Stephen has advised the following clients:

  • The Financial Services Compensation Scheme, including in relation to jurisdiction, quantum, and issues relating to judicial review.
  • The Financial Ombudsman Service, including in relation to judicial review proceedings, European law, and jurisdiction.
  • HM Treasury, including on pension scheme transfers.
  • HMRC, including in respect of sophisticated tax avoidance schemes.
  • The Bank of England, including by assisting with a large-scale investigation of corporate malpractice and judicial review proceedings.
  • Both the Serious Fraud Office and separately a party under investigation by the Serious Fraud Office.
  • A group of individual claimants in respect of negligent tax avoidance advice, reaching a settlement on favourable terms with the financial advisor.
  • A number of individual claimants on the operation of the Payment Services Regulations 2009, enabling them to recover significant sums from banks. Stephen has also advised on issues concerning consent and authorisation of payment transactions under the Payment Services Regulations 2017.
  • Legal persons affected by anti-money laundering compliance obligations.
  • Individual consumers challenging decisions of the Pensions Ombudsman.

Stephen is a frequent contributor to leading journals on financial services law and practice, including the Journal of International Banking and Finance Law and the Journal of Money Laundering Control.

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  • He does an excellent job distilling details and has a real understanding of regulators.

    Chambers & Partners

Download Commercial Litigation CV

ToggleCommercial Dispute Resolution

Stephen has a broad commercial practice. He has extensive experience of commercial litigation, arbitral proceedings, adjudications, and negotiations. He appears regularly in the High Court both by himself and as junior counsel. Stephen was recently appointed to the League Managers Association Commercial Law Panel.

Stephen has particular expertise in relation to complex contractual claims. During and since the Coronavirus pandemic, Stephen has been instructed to advise on the interpretation of high-value and complex commercial contracts, including their force majeure clauses, the doctrine of frustration, and issues regarding wrongful termination.

  • Stephen has appeared overseas as junior counsel in high-value multi-party and multijurisdictional disputes. He has experience of proceedings in Ireland, Barbados, and Saint Vincent and the Grenadines.
  • Stephen is regularly instructed in interim proceedings in the High Court concerning injunctive relief, specific disclosure applications, applications for service out of jurisdiction, and enforcement proceedings (including against high net-worth individuals and companies, domestically and overseas).
  • Stephen has been instructed in disputes concerning high value public sector contracts, including contracts concerning local government financing, NHS funding, PFI contracts, the operations of concessions, tendered contracts, and the provisions of services to the public sector.
  • Stephen has advised on the operation of section 2 of the Law Reform (Frustrated Contracts) Act 1943 in respect of an oil drilling contract.
  • Stephen has advised on an unjust enrichment claim arising in respect of facilitation agreement concerning a multi-million pound central London development.

Stephen has extensive experience of arbitral proceedings, including:

  • Stephen was instructed in a multi-million dollar arbitration concerning the defective construction of an oil rig.
  • Stephen has advised on arbitral proceedings concerning an unjust enrichment claim arising from participation in a unitised oil field in Africa.
  • Stephen has advised on an appeal/challenge to the jurisdiction of a LMAA arbitral award.
  • Stephen has drafted pleadings for arbitral proceedings in respect of disputes arising under multi-party standard form contracts.
  • Stephen has advised on the implementation and subsequent operation of the Directive for Alternative Dispute Resolution (Directive 2013/11/EU).
  • Stephen has assisted in multiple arbitrations as a Secretary or Clerk to the Tribunal. The arbitral proceedings have included a nuclear technology dispute under the ICC Rules, a dispute under the LCIA Rules concerning the financing of oil exploration, and a dispute concerning agents’ remuneration under Rule K of the Football Association Regulations.

Additionally:

  • Stephen marshalled in the Technology and Construction Court with Ramsey J and Edwards-Stuart
  • Stephen was also a contributor to ‘Wilmot-Smith on Construction Contracts’ (Oxford University Press, Third Edition), having written the chapter on mistake, frustration and misrepresentation.
  • Stephen has close familiarity with a number of overseas jurisdictions, in particular New York, where he is a qualified attorney (currently non-practising), and Israel, where he has been a Foreign Law Clerk in the Supreme Court.
  • Stephen has been invited to speak on the role and responsibilities of an Arbitral Tribunal Secretary as part of the CIArb Arbitral Secretaries’ Course.
  • Stephen has demonstrated cross-examination of underwriters and experts in the context of a reinsurance arbitration under the ARIAS Rules.
  • Stephen co-authored an article on arbitration, namely: “The Enforcement of Arbitral Awards in UAE”, (2013) Lexis PSL Arbitration.

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  • He does an excellent job distilling details and has a real understanding of regulators.

    Chambers & Partners

Download Commercial Litigation CV

ToggleInformation and Data Protection

Stephen is an experienced practitioner in information and data protection work. He has a particular specialism in data privacy and misuse of private information claims. He is ranked by both Chambers and Partners and the Legal 500 for his information law and data protection work.

Stephen is regularly instructed by central government departments, other public authorities, and  the Information Commissioner in appeals under the Freedom of Information Act and Environmental Information Regulations. Stephen also frequently acts for and advises private individuals, companies, and charities in information law and data protection disputes.

Examples of Stephen’s recent work in information law and data protection include:

  • Acting for the representative claimant in Prismall v Google and DeepMind, in which Heather Williams J considered an application to strike out a representative action regarding the transfer of the medical information of around 1.6 million patients of the Royal Free NHS Trust to Google and DeepMind. It is the first case to test the scope of the Supreme Court judgment in Lloyd v Google in the context of the tort of misuse of private information.
  • Acting for the Surveillance Camera Commissioner in R (Bridges) v Chief Constable of South Wales, which concerned the legality of the deployment of Automatic Facial Recognition technology by South Wales Police.
  • Acting for the Information Commissioner in Ticketmaster UK Ltd v Information Commissioner, which concerned the proper case management of parallel proceedings before the First-tier Tribunal and the High Court arising from a mass data breach affecting millions of consumers’ payment information.
  • Acting for the Home Office in Maurizi v Home Office and ICO, which established that the Freedom of Information Act 2000 and Environmental Information Regulations have extra-territorial application.
  • Acting for the General Medical Council in Myhill v ICO and GMC, in which the Upper Tribunal considered the proper application of the personal data exemption under the Freedom of Information Act.
  • Acting for Ofqual in Ofqual v ICO, in which the Upper Tribunal considered an appeal concerning a request for specific information regarding the difference between calculated grades and centre-assessed grades in Summer 2020.
  • Acting for the Cabinet Office in Sheppard v ICO and Cabinet Office, in which the Upper Tribunal will consider an appeal concerning an information request for internal polling information relating to policies bearing on the constitutional arrangements between the Scottish Parliament and Westminster.
  • Acting for the appellant in Scottish Power v ICO and Ofgem, in an appeal concerning a request for information concerning Ofgem’s decision to commence enforcement action on a selective basis.
  • Acting for the Ministry of Defence in Cole v ICO and MOD, in an appeal concerning a request for information regarding the use of drones by the military.
  • Acting for the appellant in Chagos Refugees Group v Information Commissioner, in an appeal concerning whether information was “held” by the FCO, and the scope of the Environmental Information Regulations’ exception for internal communications of a public authority.
  • Advising an NHS Trust on the disclosure of reports of an internal regulatory investigation into medical malpractice in the context of anticipated multi-party proceedings.
  • Acting for a Cambridge University college in a complex data protection claim, for which the claimant was seeking damages of over £2 million.
  • Acting for the Information Commissioner on a number of appeals under the Freedom of Information Act, in particular in respect of matters of national security, police investigations, and medical records.

Stephen also acts for the Government in national security cases of greatest sensitivity. He is experienced in closed material proceedings.

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  • Stephen is meticulous and thorough. He is a very calm and methodical advocate.

    Chambers & Partners
  • Stephen is calm and unflustered. He is sensible and a safe pair of hands.

    Chambers & Partners
  • Stephen is absolutely extraordinary. He is an expert, who is humble, thorough and charming.

    Chambers & Partners

Download Information, Technology & Media CV

TogglePublic International

Stephen has considerable experience and expertise in public international law. Stephen’s practice regularly encompasses advising on and litigating issues of public international law in the English courts. Stephen is currently instructed by the Foreign Office in respect of a number of public international law issues.

  • Stephen has advised on the incorporation and operation of the Palermo Convention against Transnational Organised Crime.
  • Stephen has advised the Government on the Geneva Conventions, the Convention for the Protection of Cultural Property in the Event of Armed Conflict 1954, the Bonn-Paris Conventions, and the Hague Convention Concerning the Laws and Customs of War on Land 1907.
  • Stephen has advised on customary international law governing restitution and compensation, including in respect of cultural artefacts.

Stephen also acts for the Government in national security cases of greatest sensitivity.

In the course of Stephen’s practice, he has worked extensively with leading academics, including Professor Robert McCorquodale (the Director of the British Institute of International and Comparative Law and Professor of International Law and Human Rights at the University of Nottingham) and the late Professor Vera Gowlland-Debbas (Honorary Professor of Public International Law at the Graduate Institute of International and Development Studies in Geneva and a Visiting Professor at University college London). He wrote “Wikileaks and International Law: Inviolability v Inadmissibility” [2017-18] 9 UK Supreme Court Yearbook 92 with Professor Robert McCorquodale.

Download Public International CV

Achievements

ToggleEducation

2010/2011: Bar Professional Training Course, City University.

2011: Admitted as an Attorney to the New York Bar.

2009/2010: LL.M., University of Pennsylvania Law School, Distinction.

2008/2009: BCL, University of Oxford, Lincoln College.

2005/2008: BA Law Tripos, University of Cambridge, Gonville and Caius College.

ToggleScholarships and Prizes

2010, Queen Mother’s Scholarship, Middle Temple.

2009, Thouron Award to study at University of Pennsylvania.

2009, Ralph Chiles CBE Prize for the Best Performance in Human Rights Law in Oxford University.

2008, W M Tapp Scholarship for Postgraduate Studies, Gonville and Caius College.

2008, James William Squire Scholar, University of Cambridge Law Faculty.

2008, Frere-Smith Prize for Law, Gonville and Caius College.

2007, Senior Scholar, Gonville and Caius College.

2006, Sir William McNair Law Prize, Gonville and Caius College

TogglePublications

  • An introduction to the Business Banking Resolution Scheme” (2021) 6 Journal of International Banking and Finance Law 411.
  • “Different approaches to SIPP operators’ liability” (2020) 8 Journal of International Banking and Finance Law 527.
  • “Wikileaks and International Law: Inviolability v Inadmissibility”, co-authored with Professor Robert McCorquodale [2017-18] 9 UK Supreme Court Yearbook 92.
  • “Supreme Court rules Wikileaks cable document should have been admitted into evidence”, in Lexis Nexis Butterworths News, February 2018.
  • Ensuring anti-money laundering compliance through the senior managers regime of the Financial Services (Banking Reform) Bill: Hansard brings comfort” (2014) 3 Journal of International Banking and Finance Law 179.
  • Chapter 8 on ‘Mistake, Misrepresentation and Frustration’, in Wilmot-Smith on ‘Construction Contracts’ (Third Edition, 2014).
  • The Enforcement of Arbitral Awards in UAE ”, (2013) Lexis PSL Arbitration.
  • Assistant to Justice Dr Yoram Danziger, Justice of the Israeli Supreme Court, “Changes in Methods of Freezing Funds of Terrorist Organisations since 9/11: A Comparative Analysis”, (2012) 15(2) Journal of Money Laundering Control 210.
  • Interviewed as an International Law expert by BBC Newshour, 2015.

ToggleAdditional Information

  • Appointed to the League Managers Association Commercial Law Panel.
  • Marshall in the Technology and Construction Court, March 2013.
  • Foreign Clerk with the Supreme Court of Israel, July to August 2011.
  • Admitted as an Attorney to the New York Bar, 2011, currently non-practicing.
  • Lecturer in Administrative Law at London Metropolitan University, 2011.
  • Lecturer in Constitutional Law of the European Union at London Metropolitan University, 2010.
  • German, advanced.

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  • Quotation symbol

    His advocacy style is very clear, succinct and authoritative. He’s confident on his feet, gives well-structured arguments and is authoritative.

    Chambers and Partners
  • Quotation symbol

    Stephen is a strikingly clever and very versatile lawyer who brings to bear a great deal of wisdom in his analysis.

    Chambers and Partners
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    His attention to detail is phenomenal and he has an uncanny ability to find discrete points to nail the case. Stephen thinks commercially and engages well with clients.

    Chambers and Partners
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    Very responsive and an excellent advocate.

    Chambers and Partners
  • Quotation symbol

    An excellent barrister who is very methodical in his approach.

    Chambers and Partners
  • Quotation symbol

    Stephen Kosmin is very good at presenting complex issues in a clear way and is always a pleasure to work with.

    Chambers and Partners
  • Quotation symbol

    Grapples with issues quickly and puts in the legwork to get the best outcome for the client.

    Chambers and Partners
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    He’s extremely clear in his thinking and communication. Very bright and organised.

    Chambers and Partners
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    Stephen is diligent, ultra responsive and totally reliable.

    Chambers and Partners
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    His creativity and his ability to come up with sound and strong and logical arguments make all the difference.

    Chambers and Partners
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    Stephen has a wider background in commercial law and litigation so can draw upon this knowledge and experience when dealing with data protection or privacy matters.

    Chambers and Partners
  • Quotation symbol

    Stephen is extremely bright. He is always well prepared and his is advice is robust.

    Legal 500
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    Stephen is clearly an expert in his field. He is able to cut through detailed facts to highlight the key issues.

    Legal 500
  • Quotation symbol

    Stephen is excellent. His advice is clear, easy to understand and ultimately correct. His written drafting is also of a very high standard.

    Legal 500
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    He is extremely astute. You can give him a problem and he will come back with something creative and interesting every time.

    Chambers and Partners
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    He is measured and good on his feet.

    Chambers and Partners
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    He is very diligent and will read every word of every document in order to identify every possible issue in the case.

    Chambers and Partners
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    Stephen has a tremendous intellect that is matched with his charm. An extremely hard working and effective junior.

    Legal 500
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    Stephen is very client-friendly, works incredibly hard and is all over the detail of matters, even where the factual matrix is complicated and technical.

    Legal 500
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    Very meticulous and always on top of things – he brings an extra edge.

    Chambers and Partners
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    Stephen Kosmin is someone who I’ve seen in several cases. I think he’s a very good, impressive junior

    Chambers and Partners
  • Quotation symbol

    He is really good for someone very junior. He has a big future. He’s absolutely bright and ferociously hard working. Stephen massively impressed me

    Chambers and Partners
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    He does do a lot of public law work. I love working with him. He’s extremely clear in his thinking and communication. He is very bright and organised. He is that good, I really rate him.

    Chambers and Partners
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    Stephen is a natural advocate. He has a strong legal mind and his analysis is crystal clear.

    Legal 500
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    Stephen is technically brilliant, very obliging and undoubtedly a leader in his field.

    Chambers and Partners
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    Meticulously prepared, a super brain and gains the ear of the court.

    Chambers and Partners
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    A fantastic legal brain, who is sharp on the details and good with strategy and tactics.

    Legal 500
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    Stephen is a really creative lawyer, who is well prepared and absolutely rock-solid.

    Chambers and Partners
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    He is a very impressive junior who adopts an analytical approach that breeds confidence – no stone is left unturned. He is available, engaged and good to work with. His paperwork is excellent and his advocacy is on point.

    Chambers and Partners
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    He is exceptionally quick and thorough and does not stand on ceremony. Often with the matters that we handle we need somebody who is a true team player, and Stephen is certainly that.

    Chambers and Partners
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    He is very bright and user-friendly.

    Chambers and Partners
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    Stephen is great to work with. He has tremendous knowledge and is very creative, coming up with strategies that other people wouldn’t think of and that make a big difference.

    Legal 500
  • Quotation symbol

    Stephen is very strategic and thinks outside the box. He thinks of different ways of resolving disputes.

    Chambers and Partners
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    Stephen is user-friendly and knows his way around this area of the law.

    Chambers and Partners
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    Stephen is very responsive and an excellent advocate.

    Chambers and Partners
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    Very bright, extremely well prepared and the safest pair of hands.

    Legal 500
  • Quotation symbol

    Stephen Kosmin is very, very good indeed. I highly rate him

    Chambers and Partners
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    He had everything at his fingertips. He is a polished all round advocate. I can’t think of any weaknesses. He stood out as someone who has ability beyond their years or call.

    Chambers and Partners
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    He is a very assured, thorough and competent advocate. I think he’s a future silk, and his court room matter is very assured and calm, thorough and persuasive. When he stands up, he commands attention and respect

    Chambers and Partners
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    Stephen Kosmin’s client service and general level of service, level of sophistication and commercial awareness and vision are very strong. Stephen is an excellent barrister with particular expertise in financial services matters. He is diligent, ultra-responsive and totally reliable.

    Chambers and Partners