Chris Huhne will remain in the Cabinet even if questioned under caution by police over claims he asked others to take his speeding points, Downing Street indicated yesterday.

The under-fire minister has faced allegations that he asked his estranged wife, Vicky Pryce, to take the points on her licence.

Pressure on the Liberal Democrat Energy Secretary intensified this week when it was revealed that he was the subject of a formal police investigation.

Transferring points is a serious matter and can even carry a jail sentence, although Mr Huhne has denied all the allegations.

There had been a suggestion the minister, a one-time challenger for the LibDem leadership, would have to temporarily step aside if questioned under caution.

Labour’s Peter Hain quit the Cabinet in 2008, saying that he wanted to “clear his name”, after his campaign donations were referred to police amid allegations he had breached electoral law.

But the Prime Minister’s spokesman said there had been other cases of Cabinet members questioned under caution who stayed in their post.

“It has certainly happened in the past”, he commented.

Both Mr Huhne and Ms Pryce are expected to be interviewed by police next week.

Essex police had previously said that an investigation would not be formally launched until its inquiries indicated an offence had been committed.

Mr Huhne left his wife last year after it was revealed that he was having an affair with a former public relations specialist.

Earlier this week, a Tory Cabinet colleague appeared to add to Mr Huhne’s woes.

Ken Clarke, the Justice Secretary, said that Mr Huhne appeared to be “in trouble” over the allegations. However, he added he had no reason to doubt his fellow Cabinet member.

Tony Blair was interviewed by police at the height of accusations over the loans for honours scandal, but he was not treated as a suspect, only as a witness.