The Independent Office for Police Conduct (IOPC) has identified failings in how the force handled the initial investigation and has told Scotland Yard to re-examine a discrimination claim made by the Irish writer.
The 58-year-old was detained at the major west London airport in September 2025 after flying in from Arizona, having been suspected of inciting violence across three posts on X (formerly Twitter).
Mr Linehan later received an apology from the force and a settlement – reportedly £25,000 – after filing a civil claim.
The police watchdog has confirmed that Mr Linehan subsequently requested a review into how the Met dealt with his complaint regarding the investigation, and his treatment by officers.
Graham Linehan co-created the Channel 4 comedy Father Ted
Channel 4
Received in May 2026, his application contained "an allegation that he was discriminated against due to his gender-critical beliefs".
Ruling that the Met's initial response to the complaint was inadequate, the watchdog directed the force to re-examine the discrimination claim.
An IOPC spokesman said: “In October, we found the outcome of the complaint was not reasonable and proportionate and directed the Met to reinvestigate a number of the allegations made.
“We found that, during the complaint investigation, the force failed to provide satisfactory explanations for the grounds for the man’s arrest and failed to pursue lines of inquiry regarding a complaint about the man’s bail conditions.
“We also directed them to reinvestigate the allegation that he was discriminated against.”
The watchdog said that Mr Linehan would “have a further right of review” if he remains “dissatisfied with the outcome of the force’s reinvestigation.”
Conservative politicians and Harry Potter author JK Rowling had criticised Mr Linehan’s arrest.
The Met has been contacted for comment.
Mr Linehan, as well as his work with the Channel 4 hit comedy Father Ted, also was involved with the TV sitcoms The IT Crowd and Black Books,