Nadhim Zahawi was urged on Tuesday to stand aside as Tory party chairman while his tax affairs are probed by the Prime Minister’s ethics adviser.
The call came from senior Conservative Caroline Nokes, chair of the Commons women and equalities committee.
She told BBC Breakfast: “Nadhim should stand aside until this matter is all cleared up.”
Her comments came as Mr Zahawi’s future as Tory chairman looked in increasing doubt as a minister said there were “very serious questions to answer” over his tax affairs.
Rishi Sunak on Monday ordered a probe by his ethics adviser Sir Laurie Magnus into Mr Zahawi’s tax situation saying there were “questions to answer” about it, and his compliance with the ministerial code.
But policing minister Chris Philp on Tuesday appeared to up the rhetoric, by referring to “very serious questions”.
Mr Sunak had defended the Cabinet minister at Prime Minister’s Questions last Wednesday, saying he had “addressed the matter in full”.
But the Prime Minister appears to have been unaware that Mr Zahawi had allegedly been given a penalty in reaching a settlement with HM Revenue and Customs over shares sold in YouGov, a company which he co-founded.
The BBC said on Monday that Mr Zahawi did pay a penalty as part of the deal, reported by the Guardian to be around 30 per cent, taking the total estimated settlement to around £4.8 million, though the figures have not been confirmed.
Mr Zahawi has stressed that his “error” over the YouGov shares was “careless and not deliberate”.
In a statement, he said: “I am confident I acted properly throughout and look forward to answering any and all specific questions in a formal setting to Sir Laurie.”
Ms Nokes told BBC Breakfast: “Nadhim needs to come clean on all of the questions that are being posed by journalists and others.
“We need clarity.
“It’s a really difficult situation for any Government minister when you are pretty much leading the news, on every front page this morning.”
She denied that the PM was too “weak” to remove Mr Zahawi from his post while the inquiry is carried out.
But she added: “I think Nadhim should stand aside until this matter is all cleared up.
“The longer it drags on the worse it gets for him, so I I hope the investigation is swift.
“For his own sake, he should allow there to be some space between him being a Government minister and this sort of investigation.”
Tory MP Nigel Mills, vice chairman of the all-party parliamentary group on taxation, said: “Nadhim needs to make a clear statement of what it was that triggered the alleged penalty.
“The best thing for him is to get the information out, his defence, so we can move on with or without him.”
The Tory party chairman will have a key role to play in the May local elections.
Labour has called on Mr Sunak to sack Mr Zahawi.
Mr Philp told GB News: “There are definitely very serious questions to answer.
“The Prime Minister, as soon as he became aware that there were further questions to answer over the weekend he took the decision to appoint the independent ethics adviser to look into it.
“That’s the right thing to do.
“So, let’s wait for that report to come out because until we get that report we are somewhat speculating because we don’t know exactly what happened.”
Mr Sunak emphasied on Monday that his independent adviser on ministerial interests, Sir Laurie, has been requested to “fully investigate this matter and provide advice to me on Nadhim Zahawi’s compliance with the ministerial code”.
He added that on the basis of his findings “we’ll decide on the appropriate next steps”.
Shadow foreign secretary David Lammy argued that a former Chancellor of "any previous government" in the same situation as Mr Zahawi would have "stepped down or resigned or would have been sacked".
