Rishi Sunak inadvertently broke code of conduct in wife's shares probe
Rishi Sunak broke the MPs' code of conduct when Downing Street confirmed to journalists details of a parliamentary standards investigation.
The probe was into the PM's failure to correctly declare his wife Akshata Murty's financial interest in a childminding company.
No 10 should not have commented beyond what was publicly known about it, the Commons standards committee has said.
But this was a "minor" and "inadvertent" rule breach, it added.
The probe subsequently found Mr Sunak had failed to declare Ms Murty's interest in the childminding agency properly.
In a report in August, parliamentary commissioner for standards Daniel Greenberg called that "inadvertent", saying it arose from "confusion" about the rules.
Mr Sunak accepted the conclusion and apologised.
The latest ruling, from the cross-party Commons standards committee, follows a finding by Mr Greenberg that the prime minister broke rule 13 of the MPs' code of conduct, relating to confidentiality.
This forbids parliamentarians from disclosing details of "any investigation by the Parliamentary Commissioner for Standards except when required by law to do so, or authorised by the Commissioner".
In April, No 10 provided a statement to the media containing details of Mr Greenberg's investigation into concerns Mr Sunak had not properly disclosed information about Ms Murty's shares in a childcare agency, Koru Kids, that benefited from the March Budget.
"Whilst it was open to the media to speculate, when Mr Sunak's spokesman confirmed to the media that the inquiry related to Mr Sunak's 'links to a childcare firm in which his wife is an investor' he disclosed details about my inquiry," the commissioner said.
The standards committee did not recommend any sanction against the prime minister, given the nature of the rule breach.
In an 18-page report, it concluded: "This was a minor and inadvertent breach of the Code.
"Mr Sunak's staff should not have issued any statement about the details of the case under investigation, without the approval of the Parliamentary Commissioner for Standards.
"The Commissioner has made clear that it had no impact on his inquiry. Nevertheless, it constitutes a breach that should not have occurred. However, Mr Sunak acknowledges that with hindsight he would have followed a different course of action.
"We would remind the Prime Minister, and all Ministers, like all other MPs, that it is their responsibility, as individuals, to ensure that such breaches do not occur."
The commissioner noted that Mr Sunak had indicated that "with hindsight, he would have made arrangements to restrict the disclosure of information by his office on his behalf".
Liberal Democrat chief whip Wendy Chamberlain described it as "another breach of the rules by Rishi Sunak and his chaotic Conservative government", accusing him of "continuing the same old sleaze and scandal as under Boris Johnson".
Last week, Conservative MP Marcus Fysh was ordered by the standards committee to apologise to the Commons for speaking to the media about a separate, then ongoing, investigation by Mr Greenberg.