Zac Sammour

Zac accepts instructions in all areas of commercial dispute resolution. He is often instructed in disputes that intersect with his other areas of specialism, in technology disputes, or disputes arising out of the breakdown of shareholder, director or executive employment relationships.

Zac has extensive experience of commercial matters in the High Court at all stages of proceedings, from injunctive work through to trial and appeal. He has also been instructed in proceedings in the Dubai International Finance Centre (DIFC).

Zac’s recent and current instructions include:

• SS&C v Zilo (Chancery Division). Zac acts for SS&C, a global technology company, in a multi-party team move case involving allegations of employee solicitation, document misappropriation and software copying. Zac assisted SS&C in obtaining wide-ranging imaging order relief against the Defendants at the outset of the proceedings. The proceedings are ongoing. Zac is led by Jane McCaffery KC, together with colleagues from Hogarth Chambers, and is instructed by Allen Overy Shearmen Sterling.
• Baring Investment Services v Wheeler (KBD). Zac acts for Barings, one of the world’s largest asset managers, in a claim against the former Co-Head of Barings’ Global Private Finance Group. The claim alleges breaches of contract and fiduciary duties in connection with bonus payments paid by Barings to Wheeler and other employees who resigned in a coordinated fashion following payment of their bonuses and joined a competitor. Zac is led by Jane McCafferty KC and instructed by Dechert LLP.
• Brown & Brown v The Broker Investment Group Ltd & Ors (KBD). Zac acted for the Defendants, Broker Investment Group and 11 other Defendants in a team-move case in the insurance broker industry. The claim was listed for a speedy trial but settled before trial. Zac was led by Daniel Stilitz KC and instructed by DWF Law LLP.

Sheikh Mohamed Bin Issa Al Jaber & Ors v Salfiti & Ors (Chancery Division). Zac acted for five defendants in combined and complex multi-million-pound civil fraud proceedings involving allegations of identity theft, document manipulation, bribery and secret commissions. The claim settled at trial. Zac acted throughout the proceedings, and succeeded in discharging a freezing injunction obtained ex parte against Mr Salfiti with indemnity costs ordered in his client’s favor ([2018] 11 WLUK 46). Zac was led by Olivier Kalfon, of Maitland Chambers, and acted with Charles King (also of Maitland Chambers) and James Partridge (of 2TG).

MBI International & Partners Inc (in Liquidation) v Sheikh Mohamed Bin Issa Al Jaber, Salfiti & Ors (Chancery Division). Zac acted for Mr Salfiti in a cross-border insolvency claim for c.£250 million brought by the liquidator of a BVI company. The claim against Mr Salfiti was discontinued following the exchange of witness statements.

Allen & Anr v Rabobank (Commercial Court). Zac acts for the Claimants who seek indemnification from their former employer in respect of their legal costs in defending criminal proceedings arising out of the LIBOR scandal. The claim was the subject of an unsuccessful application for summary judgment ([2020] EWHC 1902 (Comm), in which Zac was led by Richard Leiper KC).

Durlston Partners v Franco & Others (Queen’s Bench Division). Zac acted for the Claimant in a team move/breach of confidence case involving claims for breach of post-termination restraints, breaches of fiduciary duty, breaches of confidence and unlawful means conspiracy. Zac succeeded in obtaining undertakings over to a speedy trial (given at the hearing of the application for injunctive relief). The case was settled before trial. Zac was instructed by RWK Goodman.

Rollingson v Hollingsworth & Ors (Queen’s Bench Division). Zac acted for the Claimant in a team move case involving claims for breaches of contract, breaches of fiduciary duty, dishonest assistance, unlawful means conspiracy and inducement. The claim settled before trial, following an unsuccessful application by the Defendants for strike out and/or reverse summary judgment on significant aspects of the claim which raised interesting questions as to the scope of without prejudice privilege in the context of negotiations to acquire a right of action ([2020] EWHC 3568 (QB)). Zac was led by Richard Leiper KC and instructed by Lewis Silkin.

Richard Pease v Henderson Administration Ltd [2018] EWHC 661; [2019] EWCA Civ 158. Zac acted for the claimant, an investment fund manager, who brought a claim against his former employers for breach of contract arising out of its failure to pay him c. £4 million in management fees and its failure to allow him to replace the manager of a £1 billion investment fund on termination of his employment. Mr Pease successfully defended Henderson’s counterclaim for c.£2 million in the High Court, a decision which was reversed on appeal to the Court of Appeal. Zac was led in both the High Court and Court of Appeal by Richard Leiper KC, and instructed by Michelmores.

Zac also has experience of arbitration proceedings in partnership disputes.

“A real fighter, a deadly weapon, and someone you most certainly want in your corner.” Legal 500, 2025

“Zac is immeasurably smart and spots issues well before they arise”. Chambers & Partners 2025

“Zac is extremely sharp and insightful, and his drafting is superb.” Chambers & Partners 2025

“Zac is an excellent and sharp advocate.” Chambers & Partners 2025

“He is a tenacious advocate: very effective in his cross-examination and submissions” (Chambers & Partners, Employment, 2024)

Zac regularly appears as sole counsel in the Employment Tribunals and Employment Appeal Tribunal in high value and complex claims. Zac has particular experience in whistleblowing and discrimination claims, and an interest in cases involving discrimination on grounds of belief.

In addition to the commercial employment work listed above, Zac’s recent employment law work includes:

• Miller v University of Bristol. Zac acts for Professor David Miller in a high profile claim against the University of Bristol in which Professor Miller alleges discrimination on grounds of his holding anti- Zionist beliefs. An appeal to the EAT is due to be heard in 2025.
• Beldica v British Council [2024] EAT 92 Zac acted for the British Council in its successful appeal to the EAT in a case concerning the interplay between the ET’s jurisdiction, the Human Rights Act and the law of diplomatic immunity.
• Rustambekov v Fieldfisher. Zac acts for Filedfisher in a claim concerning alleged sexual misconduct by a senior associate. Fieldfisher has been granted permission to appeal to the EAT. The appeal is due to be heard in 2026.
•  Gale & Ors v Yorkshire Cricket Club. Zac acted for Yorkshire Cricket Club in relation to high profile claims for unfair dismissal, victimization and (in two cases) race discrimination brought by former coaches of Yorkshire Cricket Club who were dismissed by the Club in connection with the widely publicised allegations of racial discrimination and harassment made by former player Azeem Rafiq. Zac was successful in obtaining deposit orders in relation to claims of racial discrimination. All claims were settled before trial.
•  Thompson v Informatica, [2021] 10 WLUK 171. Zac acted for the Respondent in both the Employment Tribunal and the EAT. Before the ET, the Respondent successfully defended a whistleblowing and ordinary unfair dismissal claim brought by a senior executive who had been dismissed for breaching the employer’s anti-bribery and corruption policies. The trial was heard over 6 days. The Claimant appealed the dismissal of his unfair dismissal claim to the EAT. That appeal was dismissed.
•  Fleming v East of England Ambulance Service NHS Trust , EAT, 28 November 2017. Zac acted for the appellant, who successfully challenged a decision of the Employment Tribunal to exclude his covert recording of the private discussions of a disciplinary panel. The EAT ruled that the recordings were admissible, except those parts that were caught by legal professional privilege (led by Jane McCafferty, instructed by Steeles Law).

“ Zac is great with clients and advises on the most complex aspects of law in concise and user-friendly terms.”  Chambers & Partners 2025

“He’s excellent and very user-friendly. Clever, thoughtful and hardworking. A go-to junior for data protection”. Legal 500, 2025

“A formidable junior counsel.” (Legal 500, Data Protection 2024)

“He’s incredibly clever. He sees the arguments others do not.” (Chambers & Partners, Data Protection 2024)

“He’s pragmatic and happy to get into the weeds. He’s a strategic thinker and has good judgement for his years.” (Chambers & Partners, Data Protection 2024)

“He has a formidable intellect, he’s dynamic and he is a good team player. He is a proven performer. The written work is excellent in terms of results he achieves.” (Chambers & Partners, Data Protection 2024)

Zac has acted in a number of high profile data protection disputes. His recent and current (non- confidential) instructions include:

• TikTok v ICO. Zac acts for TikTok in its challenge to a monetary penalty notice for c.£12 million. That case has involved the first decision in the FTT on the scope of s.156 DPA, and the protection afforded to data processing “for the special purposes” [2025] UKFTT 798 (GCC). Zac is led by Anya Proops KC and Aidan Eardley KC, instructed by Bristows.
• Ashley v HMRC [2025] 4 WLR 29. Zac acted for Mike Ashley in his successful claim against HMRC for breach of his data subject rights. The judgment has been widely reported, and provides general guidance as to the subject access regime. Zac was led by Anya Proops KC, instructed by RPC.
• SMO v TikTok Inc [2022] EWHC 489. Zac acted for TikTok in representative proceedings brought by a child on behalf of all children who used TikTok, alleging wide ranging breaches of the The claim was discontinued following a hearing before Nicklin J in which the Court declined to extend time for the Claimant to serve her claim form on certain foreign domiciled defendants, and refused to permit alternative service. Zac was led by Anya Proops KC, instructed by Hogan Lovells.
• Smith & Ors v TalkTalk. Zac acted  for TalkTalk in ongoing proceedings in the Media and Communications Court brough by c.400 individual claimants alleging breaches of the DPA 1998 in relation to two data incidents that occurred in 2014 and 2015 (respectively). The Court (Saini J) struck out a claim for misuse of private information in May 2022, and granted the Claimants permission to amend other of their claims ([2022] EWHC 1311 (QB)). Zac is led by Anya Proops KC, and instructed by Mason Hayes Solicitors.
• Various Claimants v Labour Party. Zac acted for the Labour Party in high profile proceedings arising out of the leak of the Party’s internal report. The Labour Party has brought a Part 20 Claim against the individuals whom it says are responsible for the leak of that report in these proceedings (led by Anya Proops KC, instructed by Greenwoods GRM).
• Whyte v CBS Interactive Inc & Anr (Media and Communications List), a claim by the well- known boxer Dillian Whyte arising out of the publication of an article discussing Mr Whyte testing positive for a banned substance in advance of a high profile fight. Zac acts for the Defendants (led by Anya Proops KC, instructed by Howard Kennedy).
•  Newman v Southampton City Council [2020] EWHC 2148 (Fam); [2021] EWCA Civ 437. Zac acted for Ms Newman, a journalist seeking access to court documents in relation to care proceedings. Her application for access to the Court file was rejected at first instance, and her appeal to the Court of Appeal was dismissed. The claim has contributed to the ongoing debate within the Family Courts as to the proper scope of journalistic (and public) access to public law hearings, and has attracted judicial and extra-judicial comment (Led by Anya Proops KC with Kate Temple-Mabe, instructed by Howard Kennedy).
•  Facebook v Information Commissioner (EA/2018/0256). Zac acted for Facebook in its appeal against a monetary penalty notice issued by the Information Commissioner in connection with the Cambridge Analytica matter (led by Anya Proops KC with Robin Hopkins, instructed by Baker McKenzie).

Zac has appeared, both as sole and junior counsel, in a number of information law cases, including Galloway v Information Commissioner (2017) and All Party Parliamentary Group on Drones v ICO and Ministry of Defence (2017) (led by Timothy Pitt-Payne KC). He has also advised on a range of data protection issues, and has appeared in the county court in data protection matters.

“Zac’s advice is spot-on and his advocacy skills are some of the best I have seen.”  Chambers & Partners 2025

“Zac is very pragmatic, easy to deal with and clients trust him.” Chambers & Partners 2025

“Zac has a super brain that is always ticking. He is one of the best cross examiners in the business. He is exceptional in every area”  Legal 500, 2025

Zac has a developed a vibrant practice in defamation and privacy work. He is regularly instructed in cases with a data protection or employment overlap, and in traditional media and privacy disputes. Recent work include:

• Gorgianeh v Baroness Foster. Zac acted in high profile proceedings brought by a student who appeared on University Challenge with a soft toy mascot which Baroness Foster stated on Twitter had been an antisemitic symbol. The claim settled with a public apology from the Baroness, and was widely reported. Zac was instructed by Rahman Lowe.
• Oldknow v Evans [2021] EWHC 1028 (QB). Zac acted for the Labour Party in high- profile defamation proceedings brought by a former senior Labour Party official in connection with allegations made in a leaked internal report concerning the Labour Party’s handling of anti-semitism complaints (led by Anya Proops KC, instructed by Greenwoods GRM).
• Whyte v CBS Interactive Inc & Anr (Media and Communications List), a privacy claim by the well- known boxer Dillian Whyte arising out of the publication of an article discussing Mr Whyte testing positive for a banned substance in advance of a high profile Zac acts for the Defendants (led by Anya Proops KC, instructed by Howard Kennedy).

Zac has a broad public law practice, and has appeared in a number of claims for judicial review. His work encompasses human rights, local government, asylum and constitutional law. His current and recent work includes:

• Al Haq v Secretary of State for Business and Trade [2025] EWHC 1615, one of the Lawyer’s top 20 cases of 2025. Zac acted for the Claimant in its high-profile challenge to the SSBT’s decisions in 2023 and 2024 not to suspend arms-licenses for the export of parts for F-35 fighter planes to Israel in light of the ongoing war in Gaza. Zac undertook substantial advocacy at the hearing before the Divisional Court, and addressed the Court on the Claimant’s grounds relating to the Geneva Conventions and Genocide Conventions. He was led by Phillippa Kaufmann KC, Raza Hussain KC and Blinne Ni Ghralaigh, instructed by Bindmans, together with other junior colleagues from a number of chambers.
• GB News v Ofcom [2024] EWHC 2658 (Admin). Another of the Lawyer’s top 20 cases of 2025. Zac acts for Ofcom in a judicial review challenge to the lawfulness of its finding that GB News breached the Broadcasting Code in relation to its broadcasting of a “People’s Forum” programme featuring the then Prime Miniser, Rishi Sunak. Zac is led by Anya Proops KC.
• Zac acts for the Claimant in Diaspora Alliance v Secretary of State for Education in a challenge to the SSE’s decision to adopt the IHRA working definition of antisemitism as the cornerstone of a proposed training programme for schools, colleges and universities, without making proper provision for the protection of free speech and equality obligations. The claim is currently stayed.
• Zac acted for the Claimant in Bouchti v Enfield LBC [2022] EWHC 2809, a statutory review of orders providing for a lower traffic neighborhood in Enfield. The claim was dismissed by Eyre J in November 2022. Zac was led by Clive Sheldon KC.
• Zac acted for the Claimants in R (on the application of Tax Returned Ltd) v Revenue and Customs Commissioners [2022] EWHC 2515, a challenge to the adoption of a new mandatory form for claims for PAYE tax relief. The Claimants obtained permission for their claim following a contested hearing in September 2022, in which the Court granted retrospective permission for service of the Claim Form by alternative means (judgment of Heather Williams J, [2022] BTC 29. Zac is led by Joanna Clement KC, and instructed by Hill Dickinson.
• Zac acted for the Claimant in R (on the application of the Palestine Solidarity Campaign) v Secretary of State for Communities and Local Government in the High Court ([2017] EWHC 1502 (Admin)), the Court of Appeal ([2018] EWCA Civ 1284) and the Supreme Court ([2020] UKSC 16; [2020] 1 WLR 1774), a challenge to guidance from the defendant Secretary of State which sought to prohibit the administering authorities of the local government pension schemes from adopting policies of boycott, divestment and sanction against foreign nations (led by Nigel Giffin KC, instructed by Bindmans). The Supreme Court held that the challenged part of the guidance was contrary to the Padfield principle.
• Acting for the Claimant in Good Law Project v Secretary of State for Health and Social Care , a challenge to the lawfulness of the Secretary of State’s award of a number of high value contracts for the supply of PPE during the Covid-19 pandemic. The claim raised important questions as to the scope of the duties of equal treatment and transparency in the context of contracts awarded under regulation 32 of the PCR 2015, and resulted in a number of judgments on matters of procedure ([2021] 5 WLUK 226; [2021] 5 WLUK 316). Judgment on the substantive challenge is awaited.
• Zac has also acted in a number of other cases over the years, including: (R on the application of Tirkey) v the Lord Chancellor & the Director of Legal Aid Casework [2017] EWHC 3403, a challenge to the operation of the statutory charge (led by Peter Oldham KC, instructed by the Anti-Trafficking and Labour Exploitation Unit); Leicester City Council in R (on the application of Jewish Human Rights watch) v Leicester City Council in both the High Court ([2016] EWHC 1512 (Admin)) and the Court of Appeal ([2018] EWCA Civ 1551), a challenge to a resolution of the Council calling for a boycott of goods produced in Israeli settlements in the Occupied Palestinian The Council successfully defended that claim in the Divisional Court and in the Court of Appeal (led by Andrew Sharland KC), and Gulf Center for Human Rights v the Prime Minister in both the High Court ([2016] EWHC 1323 (Admin)) and the Court of Appeal ([2018] EWCA Civ 1855), a challenge against changes to the Ministerial Code (led by Jason Coppell KC and Hannah Slarks, instructed by Deighton Pierce Glynn).

Zac has extensive experience dealing with public international law issues in both domestic and international courts and tribunals. His recent work includes:

• Advisory Opinion proceedings concerning the consequences of Israel’s occupation. Zac acted for Palestine in advisory proceedings before the ICJ concerning the legal consequences arising from Israel’s occupation of the West Bank, including East Jerusalem, and the Gaza Strip. Zac was led by Philippe Sands KC and Paul Reichler, together with colleagues from outside of chambers.
• Advisory Opinion proceedings concerning the obligations of Israel in relation to the presence and activities of the UN, International organisations and Third States in the Occupied Palestinian Territory. Zac acted for Palestine in advisory proceedings before the ICJ concerning the legal obligations of Israel with respect to the UN, international organisations and third states in the Occupied Palestinian Territories. The hearings took place in May 2025. Zac was led by Paul Reichler.
• Venezuela v Guyana, Zac acts for Guyana in contentious proceedings before the ICJ concerning the boundary between it and Venezuela. Zac is led by Paul Reichler and Phillippe Sands KC, again working with a number of colleagues within and outside of chambers.
• Al Haq v Secretary of State for Business and Trade. Zac acted for Al Haq in its challenge to the SSBT’s decision not to suspend arms licenses for the supply of F-35 parts to Israel during the ongoing war in Gaza. Zac undertook the oral advocacy at the hearing before the Divisional Court on the Geneva Conventions, Genocide Convention and Articles of State Responsibility.
• Acting for the British Council in Belidca v British Council[2024] EAT 92, an appeal concerning the relationship between state immunity, diplomatic immunity and the right to fair trial under Article 6 of the European Convention on Human Rights.

Zac was involved in human rights litigation conducted in a key African jurisdiction which raised a number of important public international law and human rights law issues, and which ended successfully for his client at appellate level.

Zac acted for the Claimant in Serco v Secretary of State for Defence , a large and complex procurement challenge relating to a substantial contract worth c. £1billion. The claim settled before trial, and following a successful application by the Claimant for specific disclosure (on which the Claimant was awarded its costs on the indemnity basis: [2019] EWHC 515 (TCC)) and an unsuccessful application by the Defendant for strike out ([2019] EWHC 549 (TCC)). Zac acted for Serco throughout the proceedings, led by Joseph Barrett and instructed by DWF.

Zac has also acted as both junior and sole counsel in a number of other procurement matters. He acted for Camelot in an interlocutory hearing before O’Farell J in the IGT v Gambling Commission litigation ([2023] EWHC 1420 (TCC)).

Zac also has experience in competition law. He acted for the Claimant in Balmoral Tanks Limited v CMA in both the CAT ([2017] CAT 23) and the Court of Appeal ([2019] 4 CMLR 25; [2019] EWCA Civ 162)), the first decision of the UK courts on information exchange infringements.

Zac has experience with EU law issues outside of the context of procurement and competition law. Zac acted for a claimant in a claim for judicial review which argued that guidance issued by the Secretary of State was contrary to the IORP Directive R (on the application of the Palestine Solidarity Campaign) v Secretary of State for Communities and Local Government (led by Nigel Giffin KC).

During pupillage, Zac gained extensive experience on competition cases, including Sky v Ofcom [2015] CAT 9 (assisting David Scannell) and Speed Medical Examination Services v Secretary of State for Justice [2015] EWHC 3585, a judicial review challenging reforms to the process for handling soft tissue whiplash claims on the basis (inter alia) that they gave rise to breaches of competition law (assisting Gerard Rothschild).

Zac also gained experience during pupillage in the following areas:

•  EU sanctions;
•  The Common Agricultural Policy and;
•  Challenges to decisions of the European Medicines Agency.

“Zac is a go-to for sports work, not least his skillset within the fields of employment, data protection and litigation. Very easy to work with, client friendly and helps clients to navigate choppy waters. Extremely bright and outshines a lot of more senior barristers. Diligent, always thoroughly prepared, he wipes the floor with his opponents. Zac is a brilliant tactician and works seamlessly with solicitor teams to provide timely pragmatic and commercial advice.

‘Brilliant mind with a good eye for detail. Works very hard – prepares assiduously.’ (Legal 500, Sports Law 2024)

 Zac has recent experience in substantial sports-law cases.

• ECB v Yorkshire Cricket Club & Ors. Zac acts for Yorkshire Cricket Club in relation to ongoing disciplinary proceedings before the Cricket Discipline Commission. He also acts for Yorkshire in proceedings in the High Court.
•  Zverev v Ace Group International (Chancery Division). Zac acted for the Claimant, a prominent tennis player, in his dispute with his former manager. Mr Zverev alleged that his representation agreement with his manager was an unenforceable restraint of trade, and sought declaratory relief to that effect. The claim settled at trial (led by Anya Proops KC, instructed by Howard Kennedy).
•  Whyte v CBS. Zac acts for the Defendant to a claim brought by high-profile boxer, Dillian Whyte. The claim raises issues as to the confidentiality and privacy of anti-doping tests undertaken by professional athletes.
•  The Football League v Wigan Athletic Football Club. Zac acted for the EFL in disciplinary proceedings against Wigan Athletic arising out of the Club’s failure to pay wages as they fell due.

Zac has also advised in relation to disciplinary proceedings in tennis.