


Duncan is a Partner at our London office specialising in investigations and white collar crime.
He is regularly instructed to represent companies, boards and individuals on cross-border investigations involving issues in foreign jurisdictions and has advised on many of the major multinational cases of the last 15 years.
He has market-leading experience in Brazil, Portugal and Lusophone Africa and has also handled major matters involving Russia, China, India, South Africa, Ecuador, Kazakhstan, Saudi Arabia, Germany, Greece, Romania, the Czech Republic, Canada and Japan.
A fluent Portuguese speaker, Duncan spent two years in Brazil advising clients in investigations stemming from Lava Jato (Operation Car Wash), including the negotiation of novel leniency agreements with Brazilian prosecuting authorities and regulatory agencies. His combination of fifteen years cross-border investigations experience, on-the-ground experience in Brazil and fluency in Portuguese is unique in the London market.
Duncan represents individual clients subject to internal, regulatory and criminal investigation. He advises on all sensitivities and risks arising from such matters including legal, reputational and privacy issues and is attuned to the need to maintain relationships with government and regulatory authorities. He has acted for numerous clients in relation to public enquiries and Parliamentary Select Committee appearances.
Duncan also advises on financial sanctions and trade embargoes. He provides counsel to clients on the application of UK sanctions across a range of sectors and assists clients to comply with reporting obligations to the UK authorities, as well as handling investigations into potential sanctions breaches.
He provides expert support to General Counsel, Chief Compliance Officers and boards in relation to broader compliance issues. He leads major integrity initiatives, for example, conducting a global compliance integration for a multinational manufacturing conglomerate following a USD 5.1 billion acquisition. He regularly handles pre-acquisition anti-corruption due diligence in relation to investments into foreign jurisdictions.
Duncan advises clients on issues relating to broader governance and risk issues including non-financial misconduct, environmental breaches and in other areas where the regulatory landscape is rapidly evolving.
Duncan is ranked in the Chambers UK 2027 Guide for both Financial Crime: Individuals and Corporate Crime & Investigations, recognising his experience in handling international investigations and regulatory proceedings for both corporates and individuals. Duncan is described as “a go-to for complex, multi-jurisdictional investigations”, with a commentator noting that he is “an expert on Latin American matters and is a very astute tactician.” He is also commended for his “‘go above and beyond’ attitude to managing multi-jurisdictional cases” and “exceptional talent for problem‑solving.”
Duncan is recommended in The Legal 500 UK 2027 Guide for Regulatory Investigations and Corporate Crime. In The Legal 500, he is praised for being an “extremely clever lawyer, focused and strategic with excellent commercial acumen.” He is known in the market for having “unparalleled experience in managing simultaneous enforcement actions by multiple international regulators and achieving successful outcomes for his clients.” In previous Guides, he is further described as an “astute tactician”, and “a star.” He was listed in Global Investigations Review’s “40 under 40” in 2024.
He regularly delivers presentations on bribery, corruption, governance and effective compliance strategies, and lectures and publishes on these topics in the UK and Brazil. He co-authors the Brazil chapter of the American Bar Association International Guide to Corporate Internal Investigations.
Prior to joining Signature, Duncan was a Partner in the White Collar Defense and Investigations team at Cadwalader, Wickersham & Taft in London.
Governmental / Regulatory Corporate Investigations
Internal Investigations
Monitorships
Sanctions / Export Controls
Anti-Bribery and Corruption Due Diligence
Individual Representations
Article: Crypto that could be criminal – New Law Journal – 22 October 2026
Article: Record of £4.7 million Russian sanctions penalty signals new OFSI enforcement landscape – Thomson Reuters Regulatory Intelligence – 15 October 2026
Article: OFSI’s largest Russian sanctions penalty: Takeaways and practical tips – Global Relay Intelligence & Practice – 6 October 2026
Article: UK’s new cryptoasset regulations: FCA significantly expands remit, enforcement powers – Thomson Reuters Regulatory Intelligence – 15 September 2026
Article: Crypto meets criminal law: The UK’s new regulatory regime – Global Relay Intelligence & Practice – 11 September 2026
Article: FCA signals tougher approach to individual fines in enforcement shake-up – Financial Reporter – 16 July 2026
Article: Bigger fines, bigger risks: what UK FCA’s penalty reforms mean for individuals – Thomson Reuters Regulatory Intelligence (CUBE) – 10 July 2026
Article: FCA moves to reform policy on penalties for individuals – Global Relay Intelligence & Practice – 2 July 2026
Article: SFO Plan Focuses On Resilience But Funding Doubts Persist – Law360 – 6 May 2026
Article: Legal advice privilege and intra-client documents: widening the scope – Thomson Reuters PLC Magazine – 30 April 2026
Article: Organised crime risk and capital markets: what the Banco Master fallout means for foreign investors – Thomson Reuters Regulatory Intelligence – 12 March 2026
Article: Odebrecht in Peru: why the latest criminal charges matter for every arbitration user – Financial Regulation International – November 2025
Article: What the SFO’s new Corporate Compliance guidance means in practice –Thomson Reuters Regulatory Intelligence – 19 December 2025
Article: Collateral consequences: corruption’s ripple effect on arbitration – Litigation Finance Insider – 7 December 2025
Article: Lingering shadows: when corruption scandals generate a second wave of arbitration claims – Thomson Reuters Regulatory Intelligence – 27 November 2025
Press Quote: U.K. enforcement appetite over off-channel comms grows as U.S. wanes – Compliance Week – 1 October 2025
Article: Criminal charges in Peru matter for everyone – The Law Society Gazette – 26 September 2025
Press Quote: HSBC Using AI To Fight Fraud Under ‘Failure To Prevent’ Law – Law360 – 24 September 2025
Article: What UK’s New Prosecution Guidance Means For Compliance – Law360 – 18 September 2025
Article: Failure to prevent fraud: key takeaways for directors – Business & Accountancy Daily – 15 September 2025
Article: ANALYSIS: SFO-CPS issue corporate prosecution guidance – Thomson Reuters Regulatory Intelligence – 2 September 2025
Press Quote: Prosecutors Warn Companies Ahead Of UK Fraud Offense – Law360 – 26 August 2025
Press Quote: Financial services firms dealt tens of millions in regulatory fines – City AM – 17 July 2025
Press Quote: Signature Launches White Collar Crime and Investigations Practice with New Partner Team Hire – Corporate Counsel Business Journal – 14 July 2025
Press Quote: Mark Beardsworth and Duncan Grieve join Signature Litigation – Litigation Finance Insider – 14 July 2025
Press Quote: Revolving Doors: Linklaters adds eight-lawyer Paris team as Goodwin hires in London and Broadfield recruits from Sidley and Kirkland – Legal Business – 11 July 2025
Press Quote: The Revolving Door: Goodwin Nabs Debt Pro From Kirkland – Law360 – 11 July 2025
Press Quote: Dynamic Duo Putting a Signature on White Collar Crime – Edward Fennell’s Legal Diary – 11 July 2025
Press Quote: Signature makes twin London partner hire to launch white-collar crime practice – The Global Legal Post – 11 July 2025
Press Quote: Signature Hires 2 Pros For New White-Collar Crime Practice – Law360 – 10 July 2025
Press Quote: Signature launches new practice with white-collar duo – CDR News – 10 July 2025
Press Quote: Goodwin and Cadwalader Partners Leave to Launch Signature’s White Collar Practice – Law.com International – 10 July 2025