The prime minister urged anyone with evidence of criminal acts to talk to the police, as he faced questions about the accusations while on a visit to Norfolk.

"These are very serious, anonymous allegations," he said.

"It may be that they allude to something that is already the subject of a live police investigation, so I hope you understand it wouldn't be right for me to comment on that further specifically.

"More broadly the Conservative Party has robust independent complaint procedures in place, but I would say to anybody who has information or evidence about any criminal acts to of course talk to police, that's the right course of action."

Mr Sunak was speaking after a report in the Mail On Sunday that former Tory chairman Sir Jake Berry had sent a letter to police, in which he revealed a number of allegations about an MP had been made known to the party, but little action had been taken.

Sir Jake had only become aware of the claims when he learned the party had paid for one of the alleged victims to receive treatment at a private hospital.

His letter, written jointly with former chief whip Wendy Morton, another MP and a Downing Street official, also claimed the failure of others in the party to act had allowed the politician at the centre of the allegations to continue offending.

Deputy Prime Minister Oliver Dowden told Sky News on Sunday that the party had a "zero tolerance" approach to sexual misconduct.

Speaking on Sunday Morning With Trevor Phillips, Mr Dowden insisted the vast majority of people were in parliament were there to serve their constituents and the nation.

He also urged anyone with accusations of criminality to "go straight" to the police.

Pressed over whether there was a wider problem at Westminster after a series of scandals, Mr Dowden said: "No, I don't think there's something wrong about our parliament and the vast majority of people in parliament are there to serve their constituents and to serve the nation.

"Now, in respect of a very small number of cases, it's important robust action is taken.

"And indeed, if there are allegations, I would urge anyone to go straight to the police as a criminal matters and they should be investigated."

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It is the latest in a string of sexual misconduct claims to hit the Conservative party.

Last month, senior Tory MP Crispin Blunt was suspended by the party after being arrested on suspicion of rape and the possession of controlled substances - allegations he denies.

It came after former Conservative minister Peter Bone was suspended from the Commons for six weeks after a claim he exposed himself to a member of staff was upheld.

Chris Pincher, the former deputy chief whip, was sacked and eventually resigned after being accused of groping two men in a Tory private members' club.

And last year, former MP Imran Ahmad Khan was jailed after being found guilty of sexually assaulting a 15-year-old boy.