Greg Mailer

Greg Mailer is a partner specialising in corporate crime, financial crime, and regulatory investigations. He has experience in investigations and prosecutions by the SFO, the CPS, the CMA, the ICO and the FCA.

Greg has particular expertise in assisting clients in relation to investigations by HMRC, especially with regard to the issues of tax avoidance and evasion. He has significant experience in dealing with cases involving the Contractual Disclosure Facility (CDF) and HMRC’s Fraud Investigation Service and COP9 teams, and has acted in numerous cases in which criminal issues have arisen out of civil matters. He is a regular attendee of the Fraud Forum of HMRC, established to consult on policy and operational issues on tax fraud.

He has also acted in cases involving multi-jurisdictional corruption and bribery, Data Protection Act offences, share ramping, insolvency offences, cartel and price fixing offences, market abuse and money laundering.

Greg joined BCL in 2005 having worked for a year with HMRC.  He trained at Blake Morgan Solicitors (then Tarlo Lyons) where he gained experience in both civil and criminal litigation, having studied law at Nottingham University and completing his Legal Practice Course at Nottingham Law School.

Professional Memberships:

  • The Law Society
  • Committee member of the Fraud Lawyers Association
  • Tax Investigators Practitioners Group (a cross-disciplinary organisation comprising several hundred tax investigation specialists)
  • London Criminal Courts Solicitors’ Association


  • Running
  • MMA
  • Arsenal F.C.

What the directories have said:

“Greg is developing a big practice. He is working on tax prosecution arising out of care homes. He handles allegations of tax fraud in relation to corporate tax. He is experienced, clever and hardworking. He has a very strong strategic sense and superb expertise in tax matters – civil and criminal tax matters.

Chambers UK, 2023

“Greg is extremely knowledgeable and proactive and can provide invaluable reassurance in a complex, high-risk environment. I think his level of sophistication, his general level of service and client service and his commercial vision and awareness are all very strong.”

Chambers UK, 2023

“I think highly of both Harry and Greg and they are a great team – they were excellent. I have no hesitation to get them involved again. They are highly thought of white-collar crime lawyers with tax experience, and they were great to work with. They are also very considerate of the client, team oriented and respectful of our role too. They were great and are excellent at what they do, so are top of the list of people we would consult.”

Chambers UK, 2023

“I do rate him highly. He is endlessly available.”

Chambers UK, 2023

Greg Mailer has strong technical skills and is a very skilled negotiator and problem solver. Greg is a very safe pair of hands in the daunting environment of serious tax investigations.”

Legal 500, 2023

“Greg Mailer – a thorough and strong pair of hands for any client. He ensures that every issue or piece of evidence has been considered from every angle – an excellent person to have representing you.”

Legal 500, 2023

“I don’t know anyone as familiar as he is with navigating investigations.”

Chambers HNW, 2022

“Greg is very hardworking and clever”

Chambers UK, 2022

“He’s a very good lawyer”

Chambers Insights, 2022