An investigation is underway after a mobile phone was hidden in the House of Commons as part of a prank to play 'sex noises' during PMQs, it has emerged.

Parliament officials are said to be probing a major breach of security ahead of Sir Keir Starmer's exchanges with Kemi Badenoch in the chamber yesterday.

The phone was planted near the Commons front bench and was due to play a sexually explicit audio recording as the Prime Minister faced the Tory leader, according to The Times.

But the device was found during a routine sweep before PMQs yesterday afternoon to avoid a potentially embarrassing incident.

A source said: 'It looks like it was just a prank but it could have been much worse. We don't know how it got there.'