The General Election is the "most exciting and unpredictable" for a generation, Nick Clegg has said.
Thursday night's second televised leaders' debate had left the campaign "wide open".
Voters now had a choice between the "two old parties" - Labour and the Tories - and "something new", which the Liberal Democrat leader claimed to offer.
On a visit to Newcastle Aviation Academy he urged voters in the region to drop their traditional support for Gordon Brown's party. He said: "The North does not belong to Labour. It belongs to you - the people who live and work in the North."
Addressing students on his first public engagement of the day he said: "The debate last night showed very clearly that the General Election campaign is now wide open. In my view this is now the most exciting and unpredictable election this country has had for a generation."
Lib Dem election co-ordinator Danny Alexander repeated charges that there had been "an orchestrated smear campaign" against Mr Clegg organised by "Team Cameron".
Asked about the claims later, Mr Clegg said: "All I know of course is that there are plenty of people about who are worried that things are not going according to their plan. Their plan was just an effortless game of pass the parcel between Labour and the Conservative Party so there are lots of people both in politics and parts of the Press who don't like the fact that we are saying maybe we can do something different this time."
"They have come up with lots of reasons and some fairly unpleasant stuff as well to try and frighten people back into the old politics."
But he said people should not be "scared and intimidated" about trying something different.
Asked if he accepted the party was going to come under more scrutiny, he said: "I welcome scrutiny. There's a difference between scrutiny and abuse."