Theresa May has been accused of “scaring voters about Brexit” after warning of economic ruin and damage to the NHS and schools if Jeremy Corbyn is allowed to lead the talks.

The Prime Minister faced tough questions after launching a ferocious assault on the Labour leader’s fitness to conduct the negotiations which would “define our country for generations to come”.

In one extraordinary passage of her speech, Ms May claimed Mr Corbyn would be “alone and naked in the negotiating chamber”, without a plan for withdrawal.

She also used her most apocalyptic language yet about Britain’s fate if the talks go wrong, almost mirroring the Project Fear tactics of the Remain campaign during the Brexit referendum.

“Our economic prosperity will suffer, jobs and livelihoods will be put at risk, and with them the security and peace of mind of working families,” Ms May warned.

“If we don’t make a success of Brexit, we won’t have the financial means to fund the public services on which we all rely.

“Our National Health Service – the institution which is there for us at the most difficult times – needs us to make a success of Brexit to ensure we can afford to provide it with the resources it needs for the future.

“Every school in every village, town and city needs us to make a success of Brexit.”

Tory strategist Sir Lynton Crosby is believed to have told the Prime Minister to refocus her campaign on the choice of leader to negotiate Brexit.

It follows the disastrous U-turn on social care policy and the unravelling of the Conservative manifesto, which appeared to have sparked a Labour revival and a shrunken Tory poll lead.

Speaking in Wolverhampton, Ms May faced a suggestion that that she was so worried about the opinion polls that she was “scaring voters about the Brexit negotiations in order to get their vote”.

But the Prime Minister said the European Union had already made clear its tough stance, adding: “We need to have the strength to go into those negotiations.

“I have got the plan, I have got the will and the determination to do that.

“It would only be 11 days after polling day. The Prime Minister has to be prepared – I’m prepared, nobody else is.”

But, in fact, Ms May again failed to set out her plan, beyond leaving the single market, in order to end the free movement of EU citizens to Britain, and the willingness to walk away with no deal, if necessary.

She defended her stance that “no deal is better than a bad deal” despite a journalist’s suggestion that it risked “aeroplanes not being able to fly to the EU” and a “serious recession”.

Ms May said she, unlike Mr Corbyn, was not “willing to give anything away just to get a deal”, adding: “He wants to get the worst deal for Britain at the highest possible price.”

She also claimed her “mission”, as well as a successful Brexit, was to “shift the balance of Britain in favour of ordinary working people”.