Under-fire Nadhim Zahawi has been urged to step down by his predecessor as Tory chairman.
Senior Tory Sir Jake Berry told the BBC it is "unsustainable" for the Mr Zahawi remain in the role while Rishi Sunak's ethics adviser investigates his tax affairs.
Piling pressure on the Tory chairman, Mr Berry said the Government "needs to find a mechanism for ministers and MPs who are under investigation to step aside" temporarily.
