A second leading Conservative party donor has called for Iain Duncan Smith to face a leadership contest.
Multi-millionaire businessman John Madejski said the Conservatives needed a resolution to current uncertainty over Mr Duncan Smith's position, and claimed an election would clear the air.
His comments to BBC2's Newsnight came a day after one of the party's biggest donors, Stuart Wheeler, said there was an overwhelming case for a new leader.
The fresh challenge to Mr Duncan Smith's position topped a day in which he was dogged by questions about his future as he attempted to promote Tory education policies.
Asked whether he would like to see a leadership contest, Mr Madejski - the chairman of Reading FC, who has given £82,300 to the Tories since 2001 - told Newsnight: "It would clear the air very well at the moment, which it needs."
He added: "I think there's so much going on now that to get the situation resolved one way or another there should be an election just to confirm either Iain Duncan Smith is going to carry on as leader of the Tory party or someone new will be coming along to take over.
"But as far as I'm concerned as a would-be donor of the Tory party I think it's very important we have a democratic process in this country, and any government has a credible opposition."
Sir Michael Spicer, chairman of the Tory backbench 1922 Committee, is obliged to call the ballot if 15% of the parliamentary party - 25 MPs - call for one, which they can do anonymously.
Despite mounting speculation since the party's annual conference, that number has not been reached. However, there were predictions that MPs could strike when they return to the Commons on Monday after Mr Wheeler, who has previously given the party £5 million, said they had a duty to do so.