Nicky Morgan has said her position on Brexit means she could never run to be leader of the Tory party.
The prominent remainer said a one-nation Conservative must be on the ballot should Theresa May be toppled and called for the UK to consider joining EFTA should negotiations falter with Brussels.
But speaking at a Conservative Home event at the Conservative Party conference in Birmingham on Monday night, the former education secretary rejected speculation that was considering a tilt at the top job.
She said: “I think my position over the last two and a half years rules me out of being party leader ever.”
Turning to Brexit, she said May’s Chequers plan, which includes a common rule book on good and a customs arrangement was “the basis” for a deal, suggesting she and fellow remainers wanted more concessions.
She said: “I was delighted that Chequers actually did support and recognise things like supply chains across Europe.
“There were bits of it that were disappointing - around services, for example.”
Asked whether there was sufficient support for a Canada-style deal, which would offer a clean break from Brussels but see the UK negotiate a free trade deal, the Loughborough MP said there were enough pro-EU MPs to “knock out” the prospect.
She also said some Brexiteers were using the proposition to aim for no-deal.
“A number of people pushing Canada are quite sanguine about no-deal,” she said. “That would do enormous damage to us.”
It came as arch-Brexiteer Jacob Rees-Mogg, who leads the Tory faction the European Research Group, told a Leave Means Leave rally suggested it was not possible for remainers to frustrate Brexit should the UK be left with no option but no-deal.
He added that if the time limit of Article 50 runs out, the UK would leave and have to apply to rejoin, accepting free movement and the Euro, which he believed no-one would vote for.
“So, all we have got to do is hold our nerve until March 29 and make sure that nothing gets through Parliament that can stop Brexit, and I think that is extremely difficult given the numbers and the balance in the House of Commons - so it is steady, boys, steady,” he said.
But Morgan, who is not a supporter of a second referendum, had a stark warning about the impact of a no-deal on the Conservatives’ future prospects.
“I do genuinely believe that if there is to be a no-deal, we will put ourselves back as a party in the view of the electorate for a long, long time,” she said.
“We thought Black Wednesday kept us out of power for 13 years, no-deal and the damage that will do to the economy will be even worse.”
Morgan said MPs’ positions on Brexit would “ebb and flow” and a vote was likely in December.
She said: “If you are talking about Canada, there is more than enough to knock out Canada. It is around 40 or so.
“I think if you are talking about the number who would vote because they don’t want us to Brexit, I think the number is very small.”
Becoming a member of the European Free Trade Association, which includes Iceland, Liechtenstein, Norway, and Switzerland, should be considered, she said.
“I appreciate I’m probably going to upset a number of people in this room but so be it, that is what representatives are there to do, to upset people,” she said, turning to delegates.
“My view is that we should be thinking, and I know many Brexiteers have been thinking this, is about how we go back to being a member of EFTA, and we get access to the single market through that.
“We were a founder member of EFTA. EFTA would have us back.”