A parliamentary candidate has said he is “deeply sorry” for betting against himself winning a seat the General Election following his suspension from Labour amid an investigation by the gambling watchdog.

Kevin Craig admitted making a “stupid error of judgment” by placing a wager on the Tories defeating him in the constituency of Central Suffolk and North Ipswich, which the rival party secured by a majority of 23,391 in 2019.

He claimed he had done so because he thought he would “never win this seat” and had been planning to give any winnings to local charities.

Labour found out on Tuesday that Mr Craig was being investigated by the Gambling Commission, and moved immediately to withdraw its backing for him, it is understood.

It comes amid a wider scandal over gambling on the date of the General Election, with four Conservative candidates and officials facing a probe by the watchdog.

In a statement on Tuesday, Mr Craig said: “While I did not place this bet with any prior knowledge of the outcome, this was a huge mistake, for which I apologise unreservedly.”

He added: “I deeply regret what I have done and will take the consequences of this stupid error of judgment on the chin. I am deeply sorry to the many dedicated and loyal local Labour Party volunteers who have been supporting my campaign. I will comply fully with the investigation.”

A Labour spokeswoman said: “With Keir Starmer as leader, the Labour party upholds the highest standards for our parliamentary candidates, as the public rightly expects from any party hoping to serve, which is why we have acted immediately in this case.”

The PA news agency understands the party has also since handed back £100,000 in donations it received from Mr Craig.

Mr Craig, who founded public affairs agency PLMR and is described on its website as an expert in “political communications” and “crisis management”, was campaigning in Suffolk earlier on Tuesday, according to his social media.

The candidate posted on X, formerly Twitter, that he had attended the Ipswich Family Bank and said he hoped to “work with them to bring change after (July 4)”.

He was standing for Labour in the constituency after Dr Dan Poulter, who won the seat as a Tory, defected to the opposition party in protest at what he described as the Conservatives’ “rightward drift” and neglect of the NHS.

Dr Poulter confirmed he would not be seeking re-election in the seat in 2024.

Because nominations have closed, Mr Craig – along with Craig Williams and Laura Saunders, the two Tory candidates who have been suspended over allegations of insider betting on the election – will still be on the ballot paper.

Rishi Sunak on Tuesday pulled support for Mr Williams and Ms Saunders after having faced days of pressure to take more robust action following claims over the use of insider information to place bets on the date of the July 4 vote.

The row had overshadowed the Tory election campaign in recent days as Mr Sunak tries to close his party’s 21-point average poll deficit to Labour.

Mr Williams, who was the Prime Minister’s parliamentary aide and is standing in Montgomeryshire and Glyndwr, says he “committed an error of judgment, not an offence” and intends to clear his name.

As well as the parliamentary candidates, two senior Tory officials have taken a leave of absence at a crucial point in the campaign after also being drawn into the Gambling Commission probe.

Ms Saunders’s husband Tony Lee, Tory director of campaigning, and chief data officer Nick Mason have stepped back from their duties, while a police officer on Mr Sunak’s close protection team is also being investigated.

The Prime Minister had faced demands from within the party to act on the candidates over concerns the issue was further damaging the Conservatives’ electoral chances.

The watchdog said the probe into Mr Craig was separate from the wider inquiry into election betting.

A Gambling Commission spokesperson said: “This investigation is a separate case to the ongoing election betting investigation.

“This is an ongoing criminal investigation and the commission cannot provide any further details at this time.”