The Westminster gambling row has deepened after a Cabinet minister revealed he had placed bets on the date of the General Election.

Scotland Secretary Alister Jack denied having broken any rules but said he put three wagers on the timing of the July 4 poll, becoming the seventh politician to get drawn in to the controversy.

Rishi Sunak will face further pressure over the revelation, which comes after he caved to mounting calls from within the Tory Party to withdraw support for two parliamentary candidates facing a Gambling Commission investigation.

Labour were also dragged into the row on Tuesday, with the party suspending its Central Suffolk and North Ipswich candidate Kevin Craig after it emerged he had bet that he would lose to the Tories in the Conservative-majority seat.

Mr Jack said he had in April put £20 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 Rishi 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”.

In a statement released late on Tuesday, the minister said: “Following reports today I want to be absolutely clear I have not breached any gambling rules.”

He said that in March, he placed two unsuccessful bets on the date of the election of £5 for a vote to be 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.”

Earlier on Tuesday, Welsh Conservative member of the Senedd Russell George stepped back from the shadow cabinet after it emerged he was facing a probe by the watchdog over alleged betting on the timing of the poll.

He said he would “cooperate fully” with the investigation while Welsh Tory leader Andrew RT Davies said all other members of the Welsh Conservative Group had “confirmed that they have not placed any bets”.

The Prime Minister has withdrawn backing for two Tory candidates after coming under mounting pressure within the party to take a tougher stance on the alleged use of inside information to bet on the election timing.

Because nominations have closed, Craig Williams, who is standing in Montgomeryshire and Glyndwr, and Laura Saunders, who is standing in Bristol North West, will still appear on the ballot paper.

But a Conservative spokesman said that “as a result of ongoing internal inquiries” the party had concluded it could no longer support either of them.

Mr Williams, who was the Prime Minister’s senior parliamentary aide, said he had “committed an error of judgment, not an offence” and intended to “clear my name”.

The row has overshadowed the Tory election campaign in recent days as the Prime Minister battles to close his party’s 21-point average poll deficit to Labour.

In a sign of the widened scope of the Gambling Commission’s investigation, the watchdog passed information to Scotland Yard alleging that five more officers – in addition to a member of Mr Sunak’s protection team who was arrested earlier this month – had placed bets.

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

Ms Saunders’s husband, Tony Lee, the party’s director of campaigning, and chief data officer, Nick Mason, have stepped back from their duties.

Mr Craig, who is facing a separate probe after he placed a wager on himself losing the contest, said he was “deeply sorry” for what he described as a “stupid error of judgment”.

Labour said it had acted immediately to uphold the “highest standards” in its candidates “as the public rightly expects from any party hoping to serve”.

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

The scandal is likely to dominate Wednesday as Mr Sunak and Sir Keir Starmer go head to head in a BBC debate while campaigning enters its final stages.

A Gambling Commission spokesperson said: “We are not confirming or denying the identity of any individuals involved in this investigation.”