The former health secretary, Matt Hancock, has been found to have breached Parliament’s rules for attempting to influence an inquiry into a Conservative MP.
A standards watchdog ordered Mr Hancock to apologise for the “minor breach”.
Mr Hancock wrote a letter defending Tory MP Steve Brine, who was investigated over lobbying allegations.
Mr Hancock denied trying to influence the investigation by Parliament’s standards commissioner.
But on Monday, the Commons Committee on Standards released a report, which found Mr Hancock had made “a clear attempt to influence the commissioner’s investigation”.
The committee said Mr Hancock had breached a rule that prevents MPs from lobbying the commissioner in a way that is “calculated or intended to influence his consideration”.
Although Mr Hancock did not set out to breach the rules, had no prospect of personal gain from writing the letter, and did “not act with malice”, the committee said, he “has still not acknowledged his mistake”.
“Mr Hancock is a former cabinet minister and has been an MP for over 10 years,” the committee’s report said. “It is concerning that a member with this experience has not taken account of these provisions of the code.”
The committee recommended that Mr Hancock should make a personal statement to apologise to the House of Commons and the standards commissioner, Daniel Greenberg.
He should also attend a “briefing on his obligations under the code with the commissioner”, the committee’s report said.
The report said Mr Hancock had sent the commissioner an unsolicited letter while he was investigating Mr Brine – the chair of the Commons health committee – over claims he lobbied the NHS on behalf of a recruitment firm.
Leaked messages from 2021 showed Mr Brine had been trying contact health bosses while acting as a paid consultant for Remedium Partners, a recruitment firm offering doctors for free to the NHS.
Mr Brine, a former health minister, said he was responding to a call from ministers to help the NHS during the Covid-19 pandemic.
The texts were some of the more than 100,000 WhatsApp messages involving Mr Hancock that were leaked to the Telegraph newspaper by journalist Isabel Oakeshott.
But the commissioner, Mr Greenberg, cleared Mr Brine of paid advocacy.
During the investigation, Mr Hancock wrote a letter to the commissioner, arguing “that what Mr Brine did was acting overwhelmingly in the national interest”.
The rulebook for MPs says they should not try to influence the decision of the commissioner during an investigation into an alleged breach.
The BBC has been told that Mr Hancock will address the breach in a statement later.
Mr Hancock, who became one of the best-known politicians in the country during the Covid-19 pandemic, remains suspended as a Tory MP for for taking time off from his parliamentary duties to appear on I’m A Celebrity last year.