Tories withdraw support for Craig Williams and Laura Saunders

Ms Saunders was selected to run in Bristol North West, currently held by Darren Jones, the shadow chief secretary to the Treasury.

She is married to Tony Lee, the Tories’ director of campaigning, who has taken a leave of absence as he is also being investigated over election betting. The withdrawal of support for her as a candidate will raise new questions over his future.

Nick Mason, the party’s head of data, is also on leave after it emerged on Sunday that he is being investigated over allegedly placing “dozens” of bets.

All four Tories who have been named in relation to the scandal deny any wrongdoing.

It comes after Labour hit out at Rishi Sunak for failing to suspend the two candidates over the claims. Sir Keir Starmer accused him of “a lack of leadership” after Downing Street initially refused to act against them.

In response the Tories argued they were unable to discuss the cases as doing so could jeopardise the independent Gambling Commission investigation.

On Monday, Mr Sunak revealed that Conservative HQ had begun its own internal inquiry into the actions of those involved, paving the way for the suspension of Mr Williams and Ms Saunders on Tuesday.

Asked by reporters about that decision during a campaign trip to west London, Sir Keir said: “Why didn’t he do that last week?”