SIR Keir Starmer is being probed by Parliament's sleaze watchdog over allegations he broke rules on registering outside earnings, gifts, benefits and hospitality.

According to the website of the Parliamentary Commissioner for Standards, the Labour leader is being investigated under two sections of the MPs’ rules of conduct on registering interests.

The first strand under investigation is over declaring outside employment and earnings, while the second is around registering "gifts, benefits and hospitality from UK sources.”

Sir Keir said he was sure that he had not broken the rules, though his spokesman later said "administrative errors" had led to a "small number of late declarations."

During a visit to Wakefield for the by-election campaign, the Labour leader told broadcasters the allegations were not a surprise, adding: “My office is dealing with it and will be replying in due course.”

Asked if he was sure he had done nothing wrong, he said: “Absolutely confident, there’s no problem here.”

Sir Keir’s spokesman said “we are happy to provide” additional information that has been requested by Ms Stone.

“Keir Starmer takes his declaration responsibilities very seriously and has already apologised for the fact that administrative errors in his office have led to a small number of late declarations,” the spokesman said.

Under the Commons' code of conduct, MPs must "fulfil conscientiously the requirements of the House in respect of the registration of interests in the Register of Members’ Financial Interests.

“They shall always be open and frank in drawing attention to any relevant interest in any proceeding of the House or its committees, and in any communications with ministers, members, public officials or public office holders.”

The rules on employment and earnings say that MPs must register payments of more than £100 which they receive for work outside the Commons.

Under the section on gifts and hospitality, they must register benefits worth more than £300, or multiple benefits from the same source if they exceed that value in a calendar year.

The register shows that, as of the end of May, Sir Keir had registered earnings of £17,598.60 for legal advice given before 2020, the year in which he became the Opposition leader.

It shows the lawyer received the sum on August 24 last year for around 70 hours of work, before registering it seven days later.

Two copyright payments for books written before his election to Parliament in the London constituency of Holborn and St Pancras are also included, as is a £18,450 advance from publisher HarperCollins for a book he is writing.

Sir Keir is currently being investigated by police for his role in the so-called ‘beergate’ affair where Labour activists gathered in Durham in April last year when Covid restrictions were still in place.

He and his deputy Angela Rayner were both present at the event where beer and curry were served.

Labour initially denied Ms Rayner was present, while Sir Keir said there had simply been a food break during the course of a long evening’s work.

The party later admitted Ms Rayner was present and a leaked memo showed the meal had been planned well in advance, and was due to last 80 minutes and form the conclusion to the work event.

At the time of the Durham gathering, non-essential retail and outdoor venues including pub gardens were open, but social distancing rules – which included a ban on indoor mixing between households – remained in place.

Sir Keir has said he will resign if fined by police.