Nick Clegg has appealed to voters not to be frightened off the Liberal Democrats after a battery of hostile newspaper reports focusing on his policies and his conduct.
As the three party leaders prepared for a second televised debate, Mr Clegg said any suggestion that he had done anything wrong was "seriously out of order" as he urged the public to trust their own instincts.
The massive surge in support for the Lib Dems following last week's televised head-to-head has seen their leader coming under intense press scrutiny ahead of the TV encounter.
The Daily Express branded his immigration policies "crazy" and The Sun accused him of "wobbling", while the Daily Mail revived comments he made about Anglo-German relations in 2002 under the headline "Nick Clegg in Nazi Slur on Britain".
The Daily Telegraph, meanwhile, reported that regular payments from three Lib Dem donors were paid directly into Mr Clegg's private bank account before he became leader.
Mr Clegg said he would publish figures proving that the money had been "properly given, properly received, properly declared, properly used to pay for part of the salary of a member of my staff".
"Any suggestion I did anything wrong is out of order," he told reporters in Bristol, where tonight's 90-minute debate is being held. "I hope people won't be bullied into, be frightened into, not choosing something different. We have got a very exciting opportunity for real change in this country and I hope we will take it."
Meanwhile Tory leader David Cameron, who is under pressure to put in an improved performance after being outshone by Mr Clegg in the first debate, acknowledged that his party was facing a difficult fight. He told reporters in Exeter: "We've got a fight on our hands. There's no doubt about it. These debates are big events and we've got to do everything we can to explain to people, particularly back home sat watching the TV, why we would make a difference, what we are about, how we would change the country. People are really depressed with politics at the moment and they need to be inspired."
Foreign Secretary David Miliband sought to pile the pressure on the Conservative leader, warning that he now had to overcome his Lib Dem rival in the debate. He said: "The style debate between David Cameron and Nick Clegg will carry on. David Cameron obviously needs to deliver a knockout to Nick Clegg."
He acknowledged that Gordon Brown could not compete with his younger rivals on presentation, but said he believed that the Prime Minister's strengths would come through as voters focused on the issues. He added: "Gordon is the only man standing on that stage with the strength and the clarity to govern the country. Because opposition is about protest but the government is about tough decisions and the right decisions."