James Cleverly admitted the deepening Westminster betting row “distracts the conversation away from the really important issues”, as he declined to say whether rules around gambling on politics should be changed.

The Home Secretary said he was “furious that people who should have been motivated exclusively by public service” wagered on the election, but insisted on awaiting the outcome of Gambling Commission probe before making any decisions on rule changes.

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.

And Cabinet minister Alister Jack has admitted placing bets on the election date, although he is not being investigated by the regulator because he staked the money earlier in the year, before the period covered by the watchdog’s probe into the alleged use of inside information.

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 Cleverly said he would “much prefer” to be talking about the choice facing voters at the election.

Asked whether politicians should be banned from betting on politics during a campaign visit to Nottinghamshire, Mr Cleverly told broadcasters: “We’ll see what the Gambling Commission say because, of course, we don’t know yet whether any existing rules have been broken or whether any new rules need to be put in place.

“So we said we wouldn’t comment on the Gambling Commission’s investigation. We stick by that. We will let them do their job and we’ll listen to what they say very carefully once they’ve concluded.”

He continued: “I have said, and the Prime Minister has said, that we are furious that people who should have been motivated exclusively by public service have done this. That is why we have taken action internally as a party.”

The Home Secretary denied having ever placed any kind of political bet.

Pressed on whether it was a problem that the scandal was dominating the campaign, he said: “Of course this distracts the conversation away from the really important issues.

“It is important. We are going to let the Gambling Commission do its work. But, as I say, I’d much prefer to be talking about the low-tax choice under the Conservatives and the high-tax choice under Labour.”

The senior Tory said it was up to police forces to decide whether to suspend officers implicated in the betting row.

One of Rishi Sunak’s police protection officers was arrested on suspicion of misconduct in public office in relation to bets placed on the timing of the General Election and is on restricted duties.

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

“Police forces need to make their own decisions about professional standards,” Mr Cleverly said.

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

With polls still showing the Tories conceding a substantial lead to Sir Keir’s party, Mr Cleverly insisted Labour “have not sealed the deal”.

“I’m still talking to a lot of people who are undecided,” he told Sky News.

“They are frustrated with us. I totally get that… But when I talk about Labour, there is real concern.”

Scottish Secretary Mr Jack said he placed a £20 bet in April at odds of 5/1 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.

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.

Sir Keir said his reaction to Mr Craig showed assertive leadership “in a sharp contrast to Rishi Sunak, who took days and days and days before he took action”.

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.”

The issue is likely to feature heavily as Mr Sunak and Sir Keir 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.”