John Martyn

John Martyn:

Senior Associate

John is a senior associate in the firm’s business crime and professional discipline team and defends executives and professionals facing criminal charges and regulatory or disciplinary proceedings. 

He is experienced at dealing with high profile matters and understands the need for sensitivity, confidentiality and reputation management.  He represented Vincent Tchenguiz in his interview under caution by the SFO.  His recent clients include a senior member of a Middle Eastern royal family, TV personalities, solicitors, entrepreneurs, fund managers, art dealers, police officers and members of HM Forces.  He is regularly quoted in the national and legal press.

John is recommended in the Legal 500 as:

‘diligent, imperturbable and outstanding at dealing with tricky clients’ (General Crime) and

‘devoted to his clients and works passionately on his cases’ (Fraud: White-Collar Crime)

John often represents clients charged with historical allegations and understands the challenges of defending such matters.

Recent work

Criminal defence and police station representation

Prior to qualifying as a solicitor John served with the British Army as a special investigator, crime scene examiner and intelligence analyst. He has investigated many serious matters including sexual offences, fraud and war crimes.  John regularly represents his clients in interviews conducted by the police and his insight into police procedures is often deployed to the advantage of his clients.  Wherever possible, an effort is made to conclude matters without the involvement of the criminal courts by submitting pre-charge representations.

His defence clients include:

General crime

  • A member of a foreign royal family who was subject to an allegation of rape.  Representations were submitted in which it was asserted that the allegation had been made in an attempt to blackmail the client.  The police discontinued their investigation.
  • A school teacher, Kato Harris, in relation to false allegations of rape made by a former pupil.  The jury returned a not-guilty verdict within 15 minutes of retiring and Mr Harris was awarded costs against the CPS on the basis that the decision to prosecute was improperly made (
  • A fund manager following his arrest by the police for allegedly harassing a former work colleague.  Representations were submitted to the police disclosing evidence that the complainant was infatuated with the client.  The police discontinued their investigation.
  • The teenage son of a Russian entrepreneur who was migrating with his family to the UK.  Our client’s was found in possession of a substantial number of unlawful images.  Arrangements were made for him to undergo a course of counselling and the police subsequently agreed to deal with the matter by way of caution subject to a condition that the counselling sessions continue.  The avoidance of a criminal conviction enabled the family’s migration plans to continue uninterrupted and their son to avoid the stigma of a criminal conviction.
  • A TV personality in relation to allegations of assault and false imprisonment.  Following an interview under caution the police confirmed that they would discontinue their investigation.

Financial crime

  • A very well-known entrepreneur at his interview with the Serious Fraud Office (SFO) in relation to claims that he was involved in a fraud worth several hundred million pounds.
  • An art dealer in relation to claims that he had accepted stolen artworks on consignment.  John negotiated the return of the artworks to their country of origin and our client was not charged.
  • An entrepreneur who was alleged to have defrauded a foreign investor.  Representations were submitted that the matter was a civil dispute subject to ongoing settlement negotiations.  The police discontinued the investigation.

Victims of harassment and blackmail

John also acts for victims of crime and is adept at persuading the police to pursue complaints.  He works closely with the family and litigation teams to protect the interests of victims of harassment and blackmail. 

His cases include:

  • a US citizen who was subject to online harassment including the posting of ‘revenge porn’ by a person resident in England. The perpetrator was arrested by the police and was convicted of blackmail and imprisoned.
  • An entrepreneur who was blackmailed by a former girlfriend.  Contact was made with the blackmailer who immediately ceased contacting our client and made no further demands for payment.  The matter was completed without the involvement of the police or courts.

Local authority prosecutions

John has a particular interest in representing businesses subject to investigations by local authorities and is currently acting for a number of clients on a private basis.

Trading Standards

  • a retailer in respect of allegations that its sale comparison prices were misleading.
  • secondary ticket agents subject to a joint police and local authority investigation.
  • retailers and importers on Suspension Notices and proceedings for breaches of the Electrical Safety, Toy Safety and General Product Safety Regulations.
  • an online retailer for allegedly breaching the Packaging (Essential Requirements) Regulations.

Health & Safety/Food Safety

  • a food supplier in respect of contaminated meat products.
  • a food manufacturer following a serious work place accident.
  • a residential landlord on potential criminal liability for breaches of health and safety legislation following a suspected carbon monoxide poisoning fatality.

Planning enforcement

  • developers and landlords in enforcement proceedings for alleged breaches of Planning Enforcement Notices.

Mutual Legal Assistance/Sanctions

  • company directors, an art dealer and a solicitor in relation to international "letters of request" for interviews or witness statements for use in investigations or proceedings abroad.
  • a businessman in relation to a police investigation into money laundering and possible breach of EU/UK sanctions.

Internal Investigations

John has participated in internal investigations into:

  • alleged cartel activity by a major corporation.
  • a hedge fund suspected of covert stake building in breach of the criminal code of a European (non-EC) state.
  • a well-known charity in relation to offences committed by employees and volunteers.

Professional discipline

John advises professional clients subject to investigation/proceedings by their professional bodies, particularly where there are linked police inquiries/criminal prosecutions.  

He advises solicitors under investigation by the Solicitors Regulation Authority at all stages of the process, including making representations against the imposition of practising certificate conditions. 

John is mentioned in the Legal 500 as a key contact for professional discipline matters. 

Public law

John has represented clients in judicial review proceedings against police forces and other government bodies.