Ukip could take the Liberal Democrats' place in the next general election leaders' debates, Liam Fox has suggested.
David Cameron has previously dismissed calls for Nigel Farage to be allowed to take part in the televised discussions but that decision must be taken nearer to the time, according to the former defence secretary.
Given the party has no MPs, the assessment could be based on poll ratings, which would exclude the Conservatives' coalition colleagues, Dr Fox suggested.
He told parliamentary journal The House magazine: "That's a decision that's got to be taken much closer... but they have no Members of Parliament, so what do you do? Do you have an ICM threshold? In which case, at the moment you would probably have Labour, Conservative and Ukip."
Dr Fox insisted the Tories did not need to panic about Ukip's recent success at the ballot box, insisting much of the support was a protest rather than long term support.
"It's very hard to convince people that how they vote in Parliamentary elections will materially affect their future.
"I think first of all we don't need to panic about UKIP and I think that we have a sophisticated electorate in this country who are more than capable in using their votes differently in local elections, European elections and general elections and the era when people would vote for the same party in every kind of election with blind loyalty is behind us and I know plenty of Conservatives who would vote UKIP in a European election but never dream of voting anything than Conservative in a general election because the cost in a general election they perceive as being much greater if they get it wrong."
Dr Fox, who ran against Mr Cameron for leader, admitted to unhappiness in the party but suggested recent changes, including bringing in minister John Hayes as a contact with backbenchers, could help.
"I think we have to see how things bed down. I think undoubtedly having John Hayes there is a big step in the right direction and I think we'll see how the policy board settles down and the bottom line is that most backbenchers don't like the fact that we're in a coalition and a lot of the party is unhappy that we didn't win an overall majority in 2010 but, well, as I used to say to my patients, there's no point complaining about the air when there's nothing else to breathe. It's what were stuck with and if you don't like it then get out and work harder so we can win next time."
The eurosceptic said he has "no fear of life outside the European Union" but criticised yesterday's backbench amendment to the Queen's Speech as a "distraction" about process that had failed to acheive anything.
He also rounded on his defence successor Philip Hammond and Education Secretary Michael Gove for revealing they would vote to come out of the EU if a poll was held now.
"I think it's always better for the Cabinet not to answer hypothetical questions but I don't think it would take a genius to work out which ministers would not want to have ever closer union," he told the magazine.
"If I were a minister I would abide by collective responsibility - as I always did."
Dr Fox quit the Government over his controversial relationship with self-styled adviser Adam Werritty but indicated he would accept a return to top level politics, potentially as Chief Whip.
He added: "I read these things as well, I've decided that these conversations are conversations which if they occur at all will be conversations that I might have with the Prime Minister."
"Not for me to decide," he added. "I've got plenty of things to do with my time at the moment. I'm completing and working through the charity that I set up which is really coming to fruition now, it's a long process but that's going to be doing very well. And I'm at the final stages of the book that I'm writing."
The former cabinet minister appeared to suggest Mayor of London Boris Johnson becoming prime minister could be a step too far.
"I don't know, It's a different canvas, a very different skill. He's been a very good Mayor, he's done a very good job and we will see what Lynton brings," he said.