David Cameron insisted today that voting Conservative was the only way to get "real change", as he battled to quell the Liberal Democrat surge.
The Tory leader said the public was "grabbing on to anything new" in a bid to find a different direction for Britain.
But he warned that there was a risk the country could end up mired in "uncertainty, fudge and division".
Campaigning in south London, Mr Cameron said: "What (the public) are saying so clearly is that we are fed up with what we have got, we are fed up with the status quo..."
He went on: "They are crying out for change, they want something different.
"They are grabbing on to anything new to get change."
Mr Cameron insisted he would not turn to negative campaigning in a bid to regain the initiative in the General Election contest.
"I am going to redouble the positive. I am going to accentuate everything positive we want to bring to this country," he said.
"It absolutely clear to me what this election is now about.
"First of all, are we going to have real leadership that will bring change in our country or are we going to have uncertainty, fudge and division?"
Mr Cameron said: "For decades politicians in this country have been treating the British public like a bunch of mugs.
"Politicians have been saying 'Just give us a little bit more of your money, just let us pass one more law, one more regulation, one more little order from on high and suddenly we will solve all the country's problems.'
"It is a lie, it is a big lie, it is rubbish. It doesn't work - the old top-down, big government approach has failed in Britain.
"Even if you believed in it, even if you still believe in it. There isn't really any Government money left.
"Gordon has spent it all, it is all gone so we need something different.
"And that is where our big idea comes in.
"The idea of building the big society, the idea of saying: 'If you want change, then we have all got to pull together, work together, come together, recognise we are all in this together' and that is how you get change."
Mr Cameron went on: "Does anyone really believe that one extra piece of legislation, one more little instruction from Ed Balls going out to every school is going to make all the difference? Of course not.
"We will only get really good schools when we say to families 'You have got to get involved with your school, you have got to help back up the teachers, you have got to make sure you bring up your children properly'.
"And also when we break open the monopoly of education and say to the social enterprises, the charities and the churches and the other organisations: 'Come on in. In our big society everyone is welcome, come on in and set up a great school in the state system so we can get the competition, the choice, the excellence, the diversity that we have in the private system.'
"That is what the big society is all about.
"Take any subject you want to and you can see that the Conservatives' idea of the big society, not the big bossy state, but the big society is the way that we will get real change in our country."
Mr Cameron said the country needed "real decisive leadership" to get it out of the "economic hole" it was in.
"We have got big problems with our deficit, we have got to get on and start cutting government waste and getting value for money in government," he said.
"Are we going to get that with some fudged decision at the election? Never.
"We are only going to get it with a decisive Conservative government that gets moving on this."
He attacked what he called "Labour's jobs tax": "The idea of putting up National Insurance on every job in our country, it's a crazy idea as you are coming out of recession and into recovery.
"Are we going to stop that with some sort of indecisive result and a lot of haggling and negotiation? Of course not.
"We are only going to get that with a decisive Conservative government that starts cutting the waste and says 'No, we don't want that jobs tax'.
"Think of small businesses.
"Are we going to do that spending weeks haggling about a government? What we need is a decisive government that says 'We are going to have a Budget that helps small businesses'."
He added: "It is decisive leadership that will bring these changes that our country needs.
"If you want change... the only way to be certain of change, the only way to get change that will get the job done, is to have a Conservative government that will bring it."
Mr Cameron insisted: "The British people are crying out for change and they are going to work hard to make us deliver that change.
"But in the end, it is only a refreshed and revived Conservative Party, and a decisive Conservative victory, that can bring the change that our country needs."
Answering questions from journalists later, Mr Cameron attacked the Liberal Democrats' immigration policy and claimed an amnesty would only encourage more immigration into Britain.
He said the election campaign now needed "frankness and directness" and he would provide that.
Put to him that he should "take the gloves off" and be himself and that his big society idea was "waffle", Mr Cameron said: "What you saw just now was Cameron being Cameron and if you don't like it I am afraid there isn't another Cameron.
"That is the one, that is what there is and that is what you are going to get."
Opening his speech, Mr Cameron had appeared to joke about the Lib Dem poll surge when he said: "This General Election has suddenly got a bit lively, it's suddenly got a bit interesting, something quite big has happened. There's a new group of people that have taken centre stage in this Election."
But he went on: "That group of people are the British people. What they are saying so clearly is, 'We are fed up with what we have got'."
During a question and answer session, the Tory leader was pressed hard on Mr Clegg's position in the polls and the impact of the TV debates.
"You can ask me to comment on this poll or that poll - I would say if you want someone to comment on polls, ask a pollster," he said.
"I'm in the business of trying to change people's opinions, not commenting on them.
"I profoundly believe that if you want real, decisive change in our society; real, decisive change in our economy; and you want to sort out our political system, a decisive Conservative government will do it."
And he said: "People make up their own minds watching television debates - that's why they are such a good thing.
"It's your chance to communicate what you believe in, what you would change, to everyone watching at home.
"And that is the challenge in the remaining two debates - to do even more of that."
Mr Cameron warned that a hung parliament would result in politicians "haggling" and trying to "stitch things together", while voters could find they were "stuck with what you have got".
"We have to explain that actually if you get that, you are not going to get the decisive action and the change we need," he said.
Giving his view on the political landscape, Mr Cameron said: "People are fed up with the status quo, people are fed up with the Government, they feel it has let them down.
"They are angry, cynical, apathetic about politics and politicians of all parties because of the expenses scandal.
"They have been bruised and battered by the recession.
"They want things to change, so they are looking for who's going to deliver that change."
And he added: "We can get things done in a positive way that the others simply cannot."Reuse content