Rishi Sunak has said he is "incredibly angry" to learn of allegations that Tory candidates placed bets on the election date, calling it a "really serious matter".

The prime minister told the BBC Question Time leader's special that "it's right they're being investigated by relevant law enforcement" and he is "crystal clear that if anyone has broken the rules they should face [the] full force of the law".

Asked why those under suspicion haven't been suspended, Mr Sunak said an investigation had to take place first - but anyone guilty would be "booted out" of the party.

Laura Saunders, the candidate for Bristol North West, is married to its director of campaigns, Tony Lee. The couple are being investigated by the Gambling Commission.

Ms Saunders said she "will be co-operating with the Gambling Commission" probe, while her husband "took a leave of absence" from his role on Wednesday night, a Conservative Party spokesman told Sky News.

It comes a week after the prime minister's close parliamentary aide Craig Williams, the Tory candidate in Montgomeryshire and Glyndwr, admitted to putting a "flutter" on the election, saying this has resulted in "some routine inquiries" which he was co-operating with "fully".

Mr Sunak's close protection officer has also been arrested and suspended over alleged bets about the timing of the election.

A gambling industry source told Sky News that "more names" are being looked at, though police "are not involved" in those cases.

Data from Betfair appears to show a flurry of bets on a July poll placed on 21 May, the day before Mr Sunak called the election - including some in the hundreds of pounds at odds that would have resulted in profits in the thousands.

The prime minister was asked by an audience member, to a round of applause, if the allegations are "the absolute epitome of the lack of ethics that we have had to tolerate from the Conservative party for years and years".

He replied: "I was incredibly angry to learn of these allegations. It is a really serious matter."

"I want to be crystal clear that if anyone has broken the rules, they should face the full force of the law."

Quizzed over why the candidates have not been suspended while the investigations take place, Mr Sunak said the "integrity of that process should be respected".

He added: "What I can tell you is if anyone is found to have broken the rules, not only should they face the full consequences of the law, I will make sure that they are booted out of the Conservative Party."

Calls to suspend Tory candidates

Labour Party campaign sources told Sky News they noticed the odds of a July election narrow the day

before Mr Sunak announced it on 22 May.

Earlier, Labour leader Sir Keir Starmer called for Ms Saunders to be suspended and said it is "very telling" Mr Sunak has not already done so.

"If it was one of my candidates, they'd be gone and their feet would not have touched the floor," Sir Keir added.

Mr Sunak faced many questions about trust during the BBC grilling, with the first audience member asking if he would "confess to [a] small amount of embarrassment" after having five Tory prime ministers in the last seven years and the UK becoming something of an "international laughingstock".

The Tory leader said that "very clearly mistakes had been made" and asked the public to judge him on the last 18 months in office.

He faced shouts of "shame" when he launched an attack on the "foreign court" - the European Court of Human Rights - and also insisted he was glad he called the election when he did despite his standing in the polls plummeting further since then.

Having named the date of the election amid a 20-point deficit, the prime minister has failed to make up ground in a campaign dominated by political gaffes - notably his early exit from a D-day event.

The gambling scandal was the latest blow, after multiple projections of a historic Labour landslide and a number of big figures - from a former Tory donor to a former Tory minister - announcing they would back Sir Keir for the first time ever when polling day comes around.

Responding to Mr Sunak's BBC performance, Lib Dem Education Spokesperson Munira Wilson said the prime minister "has gone from ducking D-Day to blundering on betting".

"If he was truly angry about this scandal these Conservative candidates would have been suspended," she said.

Pat McFadden, Labour's National Campaign Coordinator, said Mr Sunak's "performance tonight was an abject failure".

The Tories hit back: "It was clear from the debate tonight that Keir Starmer will say just what he thinks you want to hear."

Mr Sunak will step up warnings about handing Labour "a blank cheque" at the election later today.

Starmer grilled on U-turns

Mr Sunak faced questions after Sir Keir took to the stage for a grilling that mainly centred around his previous support for Jeremy Corbyn and multiple policy U-turns.

The Labour leader ducked a volley of questions over whether he truly believed his predecessor would make a "great" prime minister, but said he would have been better than Boris Johnson - who went on to win in 2019.

On his U-turns, such as rowing back on a promise to abolish university tuition fees and nationalise energy, Sir Keir said he was a "common sense politician" and those pledges were no longer financially viable after the damage the Tories had done to the economy.

Mr Starmer will be in Scotland today to pledge that Labour's industrial strategy would deliver nearly 70,000 jobs.

Davey confronted over-coalition years

The event also heard from Lib Dem leader Sir Ed Davey, who faced difficult questions about his record in the coalition years and as postal affairs minister during the Horizon scandal.

Challenged by a student over his party abandoning their pledge to scrap tuition fees in the coalition era, he said: "I understand why your generation lost faith in us. It was a difficult government to be in."

On his time as postal affairs minister between 2010 and 2012, and whether he was proud of that role, he said he made "two big mistakes", including failing to initially meet campaigner Alan Bates and not seeing through assurances given to him by the Post Office that there was nothing wrong with the faulty IT system that led to hundreds of wrongful convictions.

On the campaign trail today, the Lib Dem leader will call for urgent reform to end the "appalling situation" in NHS dentistry.

Meanwhile, SNP leader John Swinney, when asked whether he was going to carry on with calling for independence "until you get the answer you want", stressed his belief that Scotland would be better as an independent country.

"I want Scotland to be like Denmark, or Ireland, or Sweden as an independent country. And when you look at those countries, they are more prosperous, they are more equal, they are fairer than Scotland and the United Kingdom," he said.

Reform UK leader Nigel Farage - who had complained about being excluded from the leaders' panel - will feature in a separate Question Time next week. He is expected to campaign in Clacton today.