Politicians should not place bets on elections, a Cabinet minister said as the Westminster gambling row deepened.

Work and Pensions Secretary Mel Stride said there should be a debate about political betting but “I would just say that people shouldn’t do it”.

But Labour leader Sir Keir Starmer said the rules were not the problem, politicians using inside knowledge were.

At least five Conservatives are being investigated by the Gambling Commission as part of its inquiry into wagers on the timing of the July 4 poll.

Labour has also been drawn into the row, suspending candidate Kevin Craig after he was investigated by the regulator for betting on himself to lose his contest in Central Suffolk and North Ipswich.

Mr Stride, a close ally of Rishi Sunak, told Times Radio the election row was “deeply disappointing” at a time when the focus should be on what a potential Labour government would do to the country.

Asked if politicians should be banned from betting on politics, he told Times Radio: “Quite possibly and I think we do need to have a debate about it.”

He added: “My personal view, I would just say that people shouldn’t do it, but I think we should have a debate about it more broadly.

“But let me be very, very clear: by saying that, I totally recognise that using inside information, as may have been the case for certain individuals in this way, is utterly wrong.”

He said he did not know the scale of the Gambling Commission’s investigation, following BBC reports that 15 Conservative candidates and officials were being looked at by the regulator.

He told LBC Radio: “I don’t know what the number is, what the number may or may not end up as, or indeed which parties may be involved, because we have obviously just heard that a Labour candidate has apparently betted against himself in the constituency in which he is standing and has been suspended as a consequence.”

Scottish Secretary Mr Jack said he placed a £20 bet in April at odds of 5 to 1 on an election being held between July and September, but that he had no knowledge of when it would be called until the day that Mr Sunak fired the starting gun on May 22.

It came after the BBC reported that he had told the broadcaster he made more than £2,000 from betting on the date, but later dismissed the comments as a “joke”.

He said that in March, he placed two unsuccessful bets of £5 on the vote being held in May and June respectively, then made the third wager in April.

Mr Jack added: “As I have said previously, I placed no bets in May and am not under investigation by the Gambling Commission.”

He told broadcasters: “I’ve never placed a political bet, I only bet on the horses. So that’s where I stand on this.

“And I don’t think that we should be lured into thinking this is a problem with the rules, it’s a problem with politicians.

“You can see from the reaction of the public that they know straight away that what’s been going on in the Tory party, this sort of insider dealing, is wrong.”

So far in the betting scandal:

– The Conservatives have pulled support from candidates Craig Williams, who was a parliamentary aide to Rishi Sunak, and Laura Saunders over bets on the timing of the election.

– Ms Saunders’ husband, the Conservative Party’s director of campaigning Tony Lee has taken a leave of absence, as has Tory chief data officer Nick Mason.

– In the Welsh Parliament, Tory Russell George stepped back from the shadow cabinet after it emerged he was facing a probe by the gambling watchdog.

– One of Mr Sunak’s police protection officers was arrested on suspicion of misconduct in public office following information passed to the Metropolitan Police by the Gambling Commission.

– A further five officers, including members of the Royalty and Specialist Command and Parliamentary and Diplomatic Command, are being investigated by the Gambling Commission.

– Labour suspended Mr Craig, who admitted to a “stupid error of judgment” by placing a wager on the Tories, claiming he thought he would “never win this seat”, which had a Conservative majority of 23,391 in 2019, and had been planning to give any winnings to local charities.

The issue is likely to feature heavily as Mr Sunak and Sir Keir Starmer go head to head in a BBC debate on Wednesday night.

A Gambling Commission spokesman said the investigation into bets on the timing of the election was “ongoing” and it “cannot provide any further details at this time”.

“We are not confirming or denying the identity of any individuals involved in this investigation.”