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Gavin Costelloe

Gavin Costelloe is a member of Greenberg Traurig’s White Collar Defense & Special Investigations Practice in London. Gavin is a former lawyer and prosecutor for the UK’s Serious Fraud Office (SFO). Gavin advises companies and individuals on internal, government and regulatory investigations and compliance issues related to the UK Bribery Act, fraud, market manipulation, anti-money laundering, economic sanctions, and other serious and complex cross-jurisdictional matters. Gavin has considerable experience assisting with diligence for mergers, acquisitions, and other investments including in jurisdictions with high corruption risk.

Gavin’s practice is focused on business crime investigation, defence, compliance, and risk mitigation. This includes assisting companies with internal, government, and regulatory investigations (including those conducted by the SFO, Her Majesty’s Revenue & Customs (HMRC), the Crown Prosecution Service (CPS) and the Competition and Markets Authority (CMA)), individual defence for senior executives and compliance professionals, and devising and implementing internal training and compliance progammes.

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On 8 September 2025, the UK’s Office of Financial Sanction Implementation (OFSI) published a Disclosure concerning breaches of Regulations 11 and 12 of the Counter-Terrorism (Sanctions) (EU Exit) Regulations 2019 (Regulations) by UK-registered and Financial Conduct Authority-regulated Vanquis Bank Limited (VBL). This instance offers another example of OFSI’s emphasis on encouraging organisations to establish effective, robust, and appropriate compliance procedures, systems, and controls to mitigate the risk of violations.
Continue Reading UK OFSI Enforcement Underscores Need for Effective Sanctions Screening and Controls

On 14 March 2025, the Office of Financial Sanctions Implementation (OFSI) issued a “Disclosure” against UK-registered and regulated charities for breaching Regulation 36 (6) of the Counter Terrorism (International Sanctions) (EU Exit) Regulations 2019 (the Regulations) by failing to respond to OFSI’s requests for information (RFI).
Continue Reading OFSI Takes Enforcement Action Against UK Charities

On 6 November 2024, the UK government published its long-awaited Guidance for the new offence of failure to prevent fraud (FTP Fraud Offence), which will…

Continue Reading UK Failure to Prevent Fraud Offence Widens Net for Corporate Criminal Liability

On 2 October 2024, the FCA issued a final notice announcing it had fined digital challenger bank Starling Bank Limited £28,959,426 for financial crime and…

Continue Reading UK Enforcement Agencies Crack Down on Financial Crime Control Failures, Sanctions Violations

On 12 September 2024, His Majesty’s Government (HMG) published the Trade, Aircraft and Shipping Sanctions (Civil Enforcement) Regulations 2024 (Regulations), introducing new civil enforcement powers…

Continue Reading UK Announces New OTSI Civil Enforcement Powers on Trade Sanctions

In a judgment handed down on 6 October, a UK Court of Appeal (the Court) provided an obiter, or non-binding, ruling expanding the scope…

Continue Reading UK Court of Appeal Expands Scope of ‘Control’ Under Russia Sanctions Regulations: ‘Mr Putin could be deemed to control everything in Russia’