A former Tory leader has warned Boris Johnson that he “should be very worried” and criticised his apology to the House of Commons.

William Hague said the prime minister had the opportunity to propose real change in response to Sue Gray’s report and squandered it.

Writing in The Times, Mr Hague said the PM had plenty of time to craft a comprehensive and substantial response which gave his critics “pause for thought” but instead “decided to do the minimum”.

“The Prime Minister could have got on the front foot, advancing his position on a broader front of ensuring integrity in government,” he said.

Bournemouth Echo: (PA)(PA)

“Yet for some reason, this very intuitive politician decided to do the minimum in responding to the report rather than go further in his apology and his proposals.

“Instead of reinforcing the momentum in his favour, he quite possibly stalled it.

“If I were him, I would be very worried about the number of his own MPs who asked unhelpful questions at the end of his statement.”

Mr Hague – who had previously said he was “appalled” by Mr Johnson’s failure to tackle the drinking culture at No 10 – reiterated the remarks he made to Times Radio last month that partygate wouldn’t have happened under any previous Tory leader.

“As Theresa May’s devastating question to him in the Commons illustrated,” he added.

Ms May had asked Mr Johnson whether he did not “read the rules”, understand them or “didn’t think the rules applied to No 10”.

Mr Hague added: “He had a chance to underline that he acknowledged that the buck stops with him and that he had to change his own methods of management. It would have cost him nothing to emphasise that.

“The mystery to me, having helped many prime ministers draft difficult statements and made hundreds of speeches in the Commons myself, is why he didn’t go further and make a more comprehensive job of it.”