Chancellor Philip Hammond is expected to warn the next Prime Minister he will have to call an election or a second referendum to break the Brexit deadlock in Parliament.
Mr Hammond is set to urge the remaining leadership candidates to be “honest with the public” about the risks of no-deal.
The Chancellor has repeatedly warned that crashing out without an agreement could be devastating for the economy.
In a speech in London, he is expected to say: “It may be that I’m wrong, and a new leader will persuade Parliament to accept the deal it has already rejected.
“Or that the European Union does a 180-degree U-turn and re-opens the Withdrawal Agreement.
But if I’m not, if the deal the current PM has negotiated is, in fact, the best deal possible - and Parliament continues to reject both it and No Deal, then the question to the candidates is not “What is your plan?”; but “What is your plan B?”.
“If the new Prime Minister cannot end the deadlock in Parliament, then he will have to explore other democratic mechanisms to break the impasse.
“Because if he fails, his job will be on the line – and so, too, will the jobs and prosperity of millions of our fellow citizens.”
