The leaders of the three main parties in the UK made history yesterday night as they crossed swords in the first ever televised prime ministerial General Election debate.

Nick Clegg started proceedings with an opening statement in which he promised that the Liberal Democrats would offer "something different".

"Do not let anyone tell you that the only choice is the old politics," he told the audience in Manchester.

"We can do something new, something different this time."

Labour leader Gordon Brown stressed that his focus was on maintaining the economic recovery over the next year, urging voters to focus on that issue.

"These are no ordinary times, and this is no ordinary election," he added.

Mr Brown warned that getting the economic decisions wrong risked a "double-dip" recession.

He also pledged to protect the NHS, police and schools as the deficit was cut.

And he said: "I know what this job involves and I look forward to putting my plan to you this evening."

Mr Cameron began by apologising for the expenses scandal, saying he hoped the debates would go some of the way to restoring the "faith and trust" in politics.

"We badly need that once again in our country," he said.

"The expenses saga brought great shame on Parliament, and I'm extremely sorry for everything that happened. Your politicians - frankly, all of us - let you down."

Mr Cameron also said there was a "big choice" at this election.

"We can go on as we are, or we can say 'No, Britain can do much better'.

We can deal with our debts, we can get our economy growing and avoid this jobs tax, and we can build a bigger society. But we can only do this if we recognise we need to join together, we need to come together, we need to recognise we are all in this together."

Mr Cameron said not everything Labour had done over the past 13 years had been wrong, and he would keep the good things.

"But we need change, and it's that change that I want to help to lead," he said. The first question from a member of the audience was on immigration.

Mr Brown said: "I know people feel that there are pressures because of immigration. That's why we want to control and manage immigration."

Labour had introduced a points system so that no unskilled workers from outside the EU could come to Britain.

"I talked to a chef the other day who was training and I said 'In future, there will be no chefs allowed in from outside the EU'," Mr Brown said.

"Then I talked to some care assistants - no care assistants come in from outside the EU.

"We are a tolerant, we are a diverse country but the controls on migration that I'm introducing and I will see go further are the right controls, the right policy for Britain."

Mr Cameron said immigration was "simply too high at the moment". The pressures on housing, health and immigration were "too great".

"I want us to bring immigration down so that it's in the tens of thousands not the hundreds of thousands," he said.

"I think we need to have not just a points system but also a limit on migration when people are coming from outside the EU for economic reasons."

There should be "transitional controls" when new countries join the EU so "they can't all come here at once".

He added: "It's been too high over these last few years and I would dearly love to get it down to the levels we had in the past so it's no longer an issue in our politics as it wasn't in the past." Mr Clegg said that, over recent years, there had been "lots of tough talking" from Labour and Conservative governments but "complete chaos" in the administration of the system.

"What I think we need to do is firstly make sure that we restore those exit controls so... we know exactly who's coming in but also when they're supposed to leave," he said.

Migrants coming to Britain should only be able to go to regions where they were needed, he added.

Mr Brown said net inward migration was falling as a result of Labour's action. Border controls meant that "we are counting people out and in from the end of this year".

He would not introduce an arbitrary cap, which would mean that an employer who needed a skilled worker would not be able to hire one.