Labour leader Sir Keir Starmer is under investigation by the Parliamentary Commissioner for Standards over potential breaches of rules on earnings and gifts.

The Parliamentary website showed on Monday that Kathryn Stone is looking at whether he broke two sections of the MPs’ code of conduct on registering interests.

A Labour source informed the Press Association news agency that the investigation is centred on a number of slightly late declarations.

However, Sir Keir has insisted he is confident that he has not broken the rules.

One strand of her investigation, which began on Wednesday, is looking at the registration of interests under the section on employment and earnings.

A second area being looked at is a possible breach of the section concerning gifts, benefits and hospitality from UK sources.

During a visit to Wakefield in West Yorkshire, the Labour leader told broadcasters the allegations are not a surprise, adding: “My office is dealing with it and will be replying in due course.”

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