Rishi Sunak will not face a sanction for breaching confidentiality rules around the investigation into his failure to declare his wife’s shares in a childcare company that benefitted from the budget.

Parliament’s standards committee, which scrutinises the behaviour of MPs, found Mr Sunak’s breach of confidentiality rules was “inadvertent”.

Standards commissioner Daniel Greenberg opened an investigation into the prime minister at the end of March following a complaint he failed to declare his wife’s shares in childcare company Koru Kids during a session before the liaison committee.

After a Downing Street spokesperson was reported as saying Mr Sunak would co-operate with the inquiry, it was expanded to examine a potential breach of the rules about confidentiality.

Mr Greenberg found Mr Sunak had broken the confidentiality rules, but noted he co-operated fully and subsequently said that “with hindsight, he would have made arrangements to restrict the disclosure of information by his office on his behalf”.

However, the matter was still referred to the standards committee as a breach was found.

The committee agreed with the findings, but also found that it was inadvertent, writing that no details that were not already public were disclosed, and not all communications from Downing Street would be directly authorised by the prime minister himself.