“Starmer accepted gifts from donors because there is no taxpayers’ money for clothing”

A spokesman for 10 Downing Street said: “We have asked the authorities for advice on our entry into office.

“We thought we were compliant, but after further questioning this month we raised additional issues.”

The House of Commons' Rules of Procedure guide states that MPs should “record any benefit given to a third party, whether or not it involves a benefit to the member himself, provided that the member has knowledge of the benefit or can reasonably be expected to have knowledge of it and that it was given by reason of his membership of the House of Commons or his parliamentary or political activities”.

Lord Alli's working relationship with the Labour leader had already proved controversial after it emerged that he had been given a security pass for Downing Street without apparently holding any government position.

The dispute was dubbed the “passport for glasses” affair because Lord Alli had previously donated clothing, accommodation and “several pairs” of glasses worth tens of thousands of pounds to the Labour leader.

“Serious violations of the rules”

A Conservative Party spokesman said: “It took just ten weeks for Keir Starmer to be investigated for his conduct.

“After Parliament has been accused of nepotism and now obviously of serious violations of parliamentary rules of procedure, the passport-for-glasses scandal must be fully investigated.

“Given Labour's cruel cuts, the millions of vulnerable pensioners across the country, forced to choose between heating and food, would no doubt jump at the chance to get free clothes just to keep warm.”

James Cleverly, Tory leadership candidate, told Sky News: “What we have to recognise is Keir Starmer and Sue Gray [his chief of staff] were very, very critical of the Conservatives on this very point – if your position is that this is what happens and we should be thoughtful and flexible in our response, then that's fine.

“But when you, like Keir Starmer, have been really aggressive in criticising the Conservatives for this, you have to make sure you are above reproach. And he has failed to do that.

“That's why I think it's absolutely legitimate to point out the hypocrisy of someone who basically got his job by criticizing others for what he's doing now.”