Question 1: How would leaders reduce the deficit without raising taxes?
First to respond was Mr Clegg who said the Lib Dems would cut fairly and look to those with the "broadest shoulders" to take the biggest burden.
Mr Cameron said the Conservatives would look for balance and find savings of £1 in every £100 that the Government spends for another two years. He said the spending and the tax would hurt working people.
Ms Wood said the "austerity experiment" had failed and that her party would not put a deadline on eliminating the deficit. She said the banks had had a bailout and now it was time for the people to have one.
The UKIP leader said the national debt had doubled in the last five years and said cuts were needed. UKIP would end "vanity projects" like HS2, scrap the foreign aid budget and stop paying money to the EU. He also said the Government should stop throwing money over Hadrian's Wall.
Mr Miliband said he would balance the books in a fairer way than in the past five years. He would start by reversing the tax cuts for millionaires and improve living standards.
Ms Bennett said the Green Party would target multinationals and rich individuals, raising taxes to pay down the deficit.
Ms Sturgeon said austerity was holding back economic growth and she did not agree with the cuts proposed by the Tories, Lib Dems or Labour.
As they went into the free-for-all, Mr Clegg then asked Mr Cameron why he was not going to ask the richest in society to pay more and yet was happy to make "ideological cuts" to schools and health services.
Mr Cameron responded by saying a Conservative government would bring in more money from tax evaders and avoiders.
However, Mr Miliband said Mr Cameron had failed to act on tax havens while Labour would introduce a tax on the rich to pay for health service improvements.
Mr Cameron said Mr Miliband wanted to put up taxes and cut people's pay. He produced a copy of the letter Labour left when the coalition came to power in 2010 which said: "I'm sorry there's no money left."
Ms Sturgeon said it was ironic to hear Mr Cameron and Mr Clegg arguing over cuts when they had been hand in glove imposing the cuts for the last five years.
She said she backed Mr Miliband on raising the top rate of tax but she said the country could not afford more cuts in the next parliament.
Mr Farage said there was no question spending got completely out of hand under Labour but added that it had not been improved over the last five years and Britain had "maxed out the credit cards".
Ms Woods accused Mr Clegg and Mr Cameron of "balancing the books on the backs of the poor".
The first furious exchange of the night was between Mr Miliband and Ms Sturgeon over the £30bn cuts programme the three largest parties were in agreement on and with which the SNP leader has said she would make a red line for any deal that would put a minority Labour in power.
Question 2: How would parties fund NHS?
Mr Farage said he would look to make cuts to the health service by reducing middle management which had increased by 48%.
He said he supported the NHS because he had needed it himself a fair few times. He would pour £3bn into the NHS by cutting the money to the EU.
Ms Sturgeon said: "Let's lift austerity invest in the NHS but without making deeper cuts elsewhere" while Ms Bennett warned against privatisation.
Mr Clegg said the NHS needed £8bn by the end of next parliament and that the Lib Dems were the only ones who had a proper plan to find that money. He said if the other leaders loved the NHS why "don't you put your money where your heart is?"
Ms Wood said the NHS was founded by people contributing together to fund the health care they needed. She said the NHS faced two threats in Wales - cuts and Labour.
Mr Miliband said Labour would take money from hedge funds engaged in tax avoidance for a Time To Care fund to hire more nurses, 8000 more doctors, 5000 for care workers, and 3000 more midwives.
He said the Government had failed because the NHS was missing cancer targets for the first time and tents had, had to been erected in which to treat patients because of the stresses on the system.
Mr Cameron spoke of his son Ivan, who died in 2009, and said: "I will never forget as the father of a desperately disabled child what I got every night when I took him to hospital worried about his health, I got unbelievable care and I want that for every family and everyone in our country."
He said the Conservatives would continue to put more money into the NHS every year and promised family doctors would open from 8am to 8pm.
The leaders are giving an uninterrupted one-minute answer to each question posed by the audience. There will then be up to 18 minutes of debate for each question. ITV said "four substantial election questions" will be addressed in all.
Leaders have not been given advance notice of the questions, which have been selected by an "experienced editorial panel".
Question 3: How would you address the issue of immigration?
Mr Miliband said he would change Labour's approach because it was not prejudiced to discuss immigration. He said under Labour those coming to the country would receieve no benefits for first two years and would make sure employers were not allowed to undercut wages and conditions. But he said he "didn't want to cut Britain off from the rest of the world."
Ms Wood said Plaid Cymru would not go along with scapegoating immigrants - she said it was bankers that caused the recession and not Eastern Europeans.
Ms Sturgeon echoed her comments saying the majority of migrants worked and that the UK should have a debate about immigration but not one "driven by the intolerance of Nigel Farage".
Mr Cameron said immigration needed to be brought under control. He said immigrants would have to work for four years and pay into the system before "taking out of the system".
Mr Farage again attempted to paint the parties as "all the same". He said it was impossible to control immigration while the UK was a member of the EU.
Mr Clegg there was "good immigration and bad immigration". He said he wanted Britain to be open for business but not open to abuse.
Ms Wood said a vote on Britain's membership of the EU should be held separately in each of the four countries - her comments were echoed by Ms Sturgeon.
The SNP leader said: "Nigel Farage wants to take the UK out of Europe. David Cameron is taking is dangerously close to the exit door. I would like to issue a challenge to David, Ed and Nick.
"They spent a lot of time talking about the UK family of nations during the Scottish referendum, but will they give a commitment that if there is an in-out referendum, no one part of that family of nations will be taken out of Europe against its will?
"Will the vote be counted in each of the four nations so none of us can be dragged out?"
Mr Miliband said if he was prime minister he would not have a referendum on Europe.
Mr Clegg said that Mr Farage thought the solution to all the UK's problem was a referendum on EU membership. He said if Britain was to leave the EU then it would lead to an increase in unemployment.
Question 4: What you will do for first time voters generation?
Ms Wood said because of the austerity measures Plaid Cymru could not afford to scrap tuition fees but would like some courses to be made available for free.
Mr Miliband said he would cut tuition fees from £9,000 to £6,000, build homes, end zero-hours contract and that he believed that the next generation should do better than the last.
Mr Cameron said he believed in creating jobs and giving young people the choice of apprenticeships and university. He also said he wanted to build homes that people could afford to buy.
Ms Bennett said that education was a public good and it should be paid for from progressive taxation. She said students should not be leaving university with an average of £44,000 of debt.
Mr Clegg again apologised for not delivering on tuition fees as he had promised in the party's 2010 manifesto but he said he had delivered on tax cuts and other measures that would make the future fairer.
Ms Sturgeon said in Scotland they had kept university attendance free and said that she had benefited from a free university education and had "no right" to take that away from the next generation.
Mr Farage said he thought that there was a section of young people who were having a great time because they were rich. He said by abolishing grammar schools it had ruined the future of a number of children who could have done better. He also said he would start a brownfield building boom.
Mr Cameron celebrated the free school programme to provide a better education.
