The ex-Lib Dem leader said his former party and Labour should be invited to help the Tories during Brexit negotiations.
He explained his bizarre idea to the BBC’s Emily Maitlis as he promoted his new book, “How to stop Brexit”.
Mr Clegg said in London this evening: “If Theresa May had announced she would be working on a cross-party collaborative basis and setting up a new standing committee or something, I would have been the first to applaud her.”
This way, he said, the Prime Minister would be able to make sure she delivered Brexit while representing a wider range of views.
However, the former Liberal Democrat leader said: “They took the decision to turn a very, very narrow mandate, based on industrial scale mendacity and a lot of opaque promises, into their particular party’s version of Brexit.”
He said Theresa May had not dealt with the question of Brexit in a “stateswomanlike” manner.
She should have taken into account the Remainers who could have come to accept Brexit, but did not want a hard break from the EU.
The Conservative Party will now have to take full blame if Brexit negotiations go wrong, he told the audience at University College London on Tuesday evening.
Mr Clegg said: “Only the Conservative party, and only this government is responsible, for screwing it up and taking full ownership of it.
“They could have shared that responsibility, but they chose not to.”
It follows calls for a Churchillian “war cabinet” to help form Brexit policy by Labour Leave campaigner Frank Skinner.
Mr Clegg also told Ms Maitlis that he believes his attempts to thwart Brexit are part of a healthy democracy.
He said: “Democracies are living breathing things, and things change, people’s opinions change – that’s why we have elections all the time.
“The whole point of a democracy, as David Davis said, and I’ve put it at the front of my book: ‘If a democracy is not able to change its mind, it then ceases to be a democracy.’”