Jeremy Corbyn is not prepared for Brexit talks that will start within days of the General Election and would find himself "alone and naked" in the negotiations, Theresa May has claimed.
The Prime Minister launched a ferocious assault on the Labour leader's fitness to run the country, insisting he has no plan for extracting the country from the European Union.
Speaking in Wolverhampton, Mrs May said that, with Brexit talks due to begin 11 days after the June 8 election, a "revealing" TV broadcast had shown "I am ready to go. Jeremy Corbyn is not".
Mrs May's speech came amid reports that campaign chief Sir Lynton Crosby has told her to refocus the campaign on the choice of leader to oversee Brexit, after a clutch of polls showed Labour narrowing the gap in the race for Number 10.
Turning her fire directly on her rival for the premiership, Mrs May said: "He is simply not ready to govern and not prepared to lead."
Looking back at Mr Corbyn's performance when questioned by Jeremy Paxman and a studio audience, Mrs May said: "He is not prepared to use the nuclear deterrent. He is not prepared to take action against terrorists. He is not prepared to give the police the powers they need to keep us safe.
"He is not prepared to take a single difficult decision for the good of our economy. He is not prepared to answer questions about his long track record of supporting people who want to harm and even attack our country.
"And with Brexit negotiations due to begin only 11 days after polling day, he is not prepared for those negotiations."
She added: "But I am prepared - prepared to take the difficult decisions that leadership demands. Prepared to do what is necessary to protect and defend our country. Prepared to go into the negotiating chamber with the EU just 11 days after polling day.
"I am prepared. I am ready to go. Jeremy Corbyn is not."
Evoking one of Labour's most revered figures, Nye Bevan - who pleaded with colleagues not to send a foreign secretary "naked into the conference chamber", in a party row over nuclear disarmament - Mrs May said: "Last night showed that Jeremy Corbyn's minders can put him in a smart blue suit for an interview with Jeremy Paxman, but with his position on Brexit he will find himself alone and naked in the negotiating chamber of the European Union."
To raucous laughter from supporters, she added: "Now, I know that's an image that doesn't bear thinking about, but actually this is very serious."
Mrs May said she would be ready "from day one" to work on a new "deep and special relationship" with the EU, while Mr Corbyn had "no plan for Brexit".
In the months since the Brexit vote, Mr Corbyn had first made a "reckless" call for talks under Article 50 to be triggered on day one after the referendum, then had "lurched chaotically from half-baked plan to half-baked plan" adopting seven different approaches to EU withdrawal, she said.
Now he was promising to tear up the Government's Brexit white paper and ditch its Great Repeal Bill, setting back the process of negotiation further, she added.
Mrs May warned: "There will be no time to waste, no way of stalling, no way of asking Europe to hang on while we figure out what to do.
"The Europeans are ready to go and are determined to fight for a deal that works for them.
"This is not time for a weak government and a weak leader to be making it up as they go along, particularly not when that leader has shown poor judgment and weak leadership throughout the process so far."
Mr Corbyn's decision to rule out walking out of Brexit talks without a deal "means being willing to accept any deal, however bad, signing up to any bill, however vast, accepting any terms, however unreasonable", she said.
"It means signing up to Britain being governed by EU laws and EU courts for years to come, so that we have no control over our laws, to free movement continuing indefinitely, so we have no control over our borders, and paying what Europe wants us to pay, so we have no control over our money either.
"As always with Jeremy Corbyn and Labour, the shambles and the responsibility would be theirs but the consequences and the bill would be ours."
Mrs May claimed that smaller parties were "queuing up" to form a coalition with Mr Corbyn and warned that - in an era of shock election results - voting for any party other than the Conservatives would be "too big a risk to take" for those who did not want to see the Labour leader in 10 Downing Street.