Andrew O'Connor QC

Year of Call: 1996 / Year of Silk: 2015

Practice Areas

Andrew O'Connor QC


Andrew O’Connor has extensive experience of public law and general common law litigation. In recent years, he has also appeared in a series of high profile inquests and inquiries, including the 7/7 inquests, the Hillsborough inquests and the Litvinenko Inquiry. He is currently instructed in the The Independent Inquiry into Child Sexual Abuse, The Undercover Policing Inquiry and in the inquests into the deaths of those killed in the terrorist incident at Sousse, Tunisia.

Prior to taking silk in 2015, he was a member of the Attorney General’s civil litigation panels for 14 years, latterly the A Panel from 2011. He is developed vetted and much of his work for government clients has been in the field of national security. He is listed as a New Silk for Administrative Law and for Inquests and Inquiries in both the 2016 edition of Chambers UK and the 2015 edition of the Legal 500.  He was previously listed as a Band 1 Junior in both categories.


Chambers UK 2016 Administrative & Public Law:  “He’s excellent – his judgement is sound, he works hard and he is incredibly easy to deal with.” “He is extremely bright and a very tough litigator with real authority in front of the court.”

Professional Memberships

Administrative Law Bar Association

Tunisia Inquests

Andrew O’Connor QC is instructed to act for HMG in the inquests into the deaths of the 30 British nationals who died in the terrorist attack at Sousse, Tunisia in June 2015.

The Independent Inquiry into Child Sexual Abuse

Andrew O’Connor QC is instructed by the Inquiry to act in the investigation into child sex abuse in Westminster.
Cathryn McGahey QC is Leading Counsel for The Department for Education

Bredenkamp v Foreign Secretary

Andrew O’Connor QC was instructed to act for the Foreign Secretary in judicial review proceedings arising from EU sanctions regime relating to Zimbabwe.

The Litvinenko Inquiry

Inquiry into the death of Alexander Litvinenko, who died from Polonium poisoning in 2006.

Undercover Policing Inquiry

Major statutory public inquiry into undercover policing chaired by Sir John Mitting, retired High Court Judge.  David Barr QC has been appointed Counsel to the Inquiry. Andrew O’Connor QC is instructed to act for National Crime Agency.

Mohamed & another v SSHD [2014] 1 WLR 4240

Control order / TPIM matter, where the CA decided that the reasons for rejecting the abuse of process case of suspected terrorists in control order / TPIM proceedings could not be confined to a closed judgment

The Gareth Williams Inquest

Instructed to act for MI6 and GCHQ in the inquest into the death of Gareth Williams, whose body was found inside a locked bag in the bath of his flat.

The Tomlinson Inquest

Instructed to act for the IPCC in the inquest into the death of Ian Tomlinson, who died at the G7 protests in London.

The 7/7 inquests

Instructed as Junior Counsel to the Inquests into the deaths of the 52 victims of the 7/7 bombings.

HM Treasury v Ahmed & others [2010] UKSC 2; [2010] 2 WLR 378

Instructed to act for HM Treasury in judicial review proceedings heard by the Supreme Court concerning the legality of domestic secondary legislation implementing UN terrorist sanctions regimes.

Andrew O’Connor QC appeared at the first preliminary hearing of the IICSA Westminster investigation

31st January 2018

Andrew O’Connor QC appeared at the first preliminary hearing of the IICSA Westminster investigation today. He is instructed as the Inquiry’s lead counsel on the Westminster investigation. Substantive hearings for the Westminster Investigation are due to take place in March 2019.

Andrew O’Connor QC acts for intelligence agencies in challenge to bulk data policies

19th October 2017

Andrew O’Connor QC is acting for MI5, MI6 and GCHQ in proceedings before the Investigatory Powers Tribunal.  The case concerns the legality of the agencies’ policies for acquiring and holding bulk datasets.

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Andrew O’Connor QC represented HMG at the Inquests into the deaths of 30 British nationals killed at Sousse, Tunisia in 2015

2nd March 2017

On 28 February 2017 verdicts were returned of unlawful killing and the Coroner stated that he will be receiving further submissions on the content of any report on future deaths in the coming weeks.

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Andrew O’Connor QC appears before the IPT in the ‘Bulk Data Judgment’

1st November 2016

Andrew O’Connor QC, as part of a team composed of James Eadie QC, Andrew O’Connor QC and Richard O’Brien, appeared for the Foreign Secretary, the Home Secretary, GCHQ, the Security Service (MI5) and the Secret Intelligence Service (MI6), the Respondents in a claim made by Privacy International in the Investigatory Powers Tribunal.

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Privacy International

27th July 2016

Andrew O’Connor QC is representing MI5, MI6 and GCHQ in a challenge brought by the campaign group Privacy International relating to the agencies’ practices in acquiring and making use of bulk personal datasets and bulk communications data.  The proceedings are taking place before the Investigatory Powers Tribunal.