Sebastian Gardiner
  • Driven by a strong sense of justice means he is well liked by clients as he fights their corner with every tooth and nail.

    Legal 500 2026, Crime

  • He is very capable in dealing with complex drug cases. He knows his way around any issues surrounding such cases.

    Chambers UK 2026, Crime

  • He is forthright, clear and compelling.

    Chambers UK 2025, Crime

  • Sebastian is very effective in communicating his approach.

    Chambers UK 2025, Crime

  • Sebastian is a dedicated defence advocate to the tips of his fingers.

    Legal 500 2025, Crime

  • Sebastian is hard-working, efficient, client friendly, a fine tactician with sound judgment, an excellent lawyer, a powerful presence in court, and a very persuasive speaker.

    Legal 500 2025, Crime

  • There is nothing Seb doesn't know. He's familiar with his case inside and out.

    Chambers UK 2024, Crime

  • Sebastian is an imposing figure in court.

    Legal 500 2024, Crime

  • He is an assured advocate with a sound appreciation of forensic strategy and a highly effective cross-examiner, able by his skill and careful preparation to extract the right answers from recalcitrant prosecution witnesses.

    Legal 500 2024, Crime

  • His legal submissions are concise, accurate and persuasive.

    Legal 500 2024, Crime

  • Sebastian is an outstanding advocate.

    Legal 500 2023, Crime

  • He is an expert in EncroChat cases which are huge, pressurised and detail-laden cases. He also really cares about the progression of the profession.

    Chambers UK 2023, Crime

  • He has great attention to detail, has the ability to foresee where problems might arise, is extremely thorough and robust where appropriate. His preparation is second-to-none.

    Legal 500 2023, Crime

  • He is organised, cerebral and excellent with clients.

    Chambers UK 2022

  • Sebastian is an excellent lawyer. He has a very good analytical mind and often identifies more obscure points of law.

    Legal 500 2022, Crime 

  • He is rigorous in his preparation of cases and his advocacy is of a very high standard. He has developed extensive knowledge in a number of areas of criminal law and regularly acts for defendants facing very grave charges.

    Legal 500 2022, Crime

  • He has a "good eye for detail" and "excellent knowledge of the law".

    Chambers UK 2021

  • Sebastian works incredibly hard and really grasps every detail through his forensic-like approach.

    Legal 500 2021

  • He is fantastic with clients who regularly comment on just how happy they are with his ability and manner in dealing with the evidence and their instructions. In court, Sebastian has a way that holds everyone's attention. A very skilful advocate.

    Legal 500 2021

  • A fearless and dogged advocate in challenging criminal trials where prosecution evidence must be faced head-on.

    Legal 500 2020

  • His work includes challenging murder cases.

    Legal 500 2018

Called 1997

Sebastian Gardiner

Barrister

Sebastian Gardiner is a leading junior in chambers. He is regularly instructed in all areas of serious crime, predominantly allegations of murder, large scale drug supply and importation cases as well as major fraud offences.

Recommended as a Leading Junior in Crime in Chambers UK 2025 and the Legal 500 2026.

He has developed a particular expertise in offences under the Misuse of Drugs Act and, over the last few years, he has been involved in some of the largest drugs cases in the UK.

Sebastian regularly gives lectures to members of the legal profession on developments in drugs legislation and sentencing. He provides advice to both professional and lay clients and other professional bodies concerning drugs offences, sentencing and conviction. He has developed a particular expertise in prosecutions linked to Operation Venetic and evidence obtained from the Encrochat communications network, and analysis of mobile phone data.

As well as specialising in drug related offences, he is regularly instructed in murder and fraud offences.

Sebastian has a keen interest and expertise in issues surrounding the right to protest and to lawful assembly. He has provided advice on police powers and prosecutions for matters relating to civil disobedience and non-violent direct action.

He is Head of Pupillage in Chambers and was previously the chairman of the crime group of the Society of Labour Lawyers.

Sebastian is qualified to accept instructions via Direct Access.

Associated Work

  • Lectured on various aspects of Misuse of Drugs Act and Encrochat cases/the Investigatory Powers Act.
  •  Edited publication for  RELEASE and other organisations.
  • In-house lectures on Criminal Procedures and Investigations Act [1996], and Criminal Justice Act [2003].

Professional Memberships

  • Criminal Bar Association
  • Society of Labour Lawyers
  • RELEASE
  • The Howard Reform League
  • Liberty
  • Association of Regulatory and Disciplinary Lawyers (ARDL) 
  • Chambers Ambassador to the Bar Council