The leaders of the three main parties, Tony Blair, Michael Howard and Charles Kennedy faced questions from a live TV audience for the BBC's Question Time.
LIB DEM LEADER CHARLES KENNEDY
The first topic of questioning was council tax - Mr Kennedy said the Lib Dems would bring in a fairer system, a local income tax.
The Lib Dem leader accepted a household with income over £42,000 would pay more under his policy.
He said the big winners would be pensioners but there would be some losers under the local income tax.
The Lib Dems were being brave in being honest about their plans, Mr Kennedy insisted.
The average annual saving under their local tax plans would be £450 per household, he said.
Some households which paid more in local income tax would benefit from plans to abolish student fees, he added.
Asked about Iraq, Mr Kennedy said the Lib Dems believed there should be a phased withdrawal of troops. He denied this would endanger Iraqi civilians.
He said the publication of the advice from the attorney general on Iraq was not a "damp squib" as Tony Blair said - particularly for those people who had lost family members in the war.
He said everyone was pleased to see the back of Saddam but the continuing US-led coalition troop presence was encouraging insurrectionists.
The Lib Dem leader suggested they could be replaced with Muslim forces under a UN charter.
He said the lack of a body count of Iraqi citizens killed since the invasion was wrong and a shame to this government.
Under the UN charter our country can defend itself, Mr Kennedy argued, but it cannot go into another country to change its government.
Mr Kennedy said he had told US President George W Bush he did not agree with his policy in Iraq.
But he denied being anti-American and said it would make no difference to relations with the US if the UK leadership changed.
Challenged about his "lack of charisma" as a leader, Mr Kennedy said the Lib Dems' stance on the war had been quite courageous.
He said the Lib Dems had a higher level of support in this campaign than at any time in recent years.
The Conservatives cannot win this election and Labour has let people down, he said, so voters are looking at the Lib Dems.
Mr Kennedy said, if elected, he would bring in proportional representation because the present voting system is "perverse".
Too many people's votes are corrupted by tactical voting, he said. He would like people to vote for principles.
TORY LEADER MICHAEL HOWARD
The first question put to Michael Howard was on the issue of immigration.
Mr Howard said he would do what was best for Britain, bringing in a fair system and limits on immigration.
He said his father came as an economic migrant - and the Tories would still allow that, up to the limits on numbers they set.
There would be three groups of people let in, the Conservative leader said, people with skills that were needed, people with family here and genuine refugees.
Mr Howard said doctors and nurses would still be able to come in to the UK.
Many health workers were leaving because they were unhappy with the NHS, he said, and the Tories would improve working conditions so more stayed in the health service.
Mr Howard said a sensible international agreement was needed on immigration.
Asked if he would pull out of the 1951 UN refugee convention, Mr Howard said he believed it was out of date.
He argued he wanted to stop money going to people traffickers - and a fairer immigration system than exists at present.
Asked about negative campaigning, Mr Howard set out the Tories' main policy points.
He said voters must look at the choice between parties' policies - and whether pledges would be followed through.
Pressed about his use of the word "liar", Mr Howard asked the audience if they thought Tony Blair had lied over Iraq.
He said he had been honest and direct - and stressed that people's record on honesty was important.
Challenged by an asylum seeker over the language he used on immigration, Mr Howard said he wanted "more genuine refugees than come today" rather than people paying traffickers.
In a series of exchanges on Iraq, Mr Howard insisted he would have gone to war in the same circumstances because it was the right thing to do.
But he said it was possible to go to war and tell the truth - and to have a proper plan for after Saddam Hussein was deposed.
The Tory leader said he would have gone to war knowing that there were no WMD because Saddam Hussein was a threat to the region and in breach of UN resolutions.
Asked if he would support regime change elsewhere, Mr Howard said other factors were necessary to justify war.
Mr Howard said even if it was "politically inconvenient" to say so now, he would still have gone to war.
He would love to be able to get rid of Robert Mugabe in Zimbabwe, Mr Howard said, but he was not a threat to the region in the way Saddam Hussein had been.
The Tory leader said he would maintain a nuclear deterrent.
Questioned on his party's spending plans, Mr Howard said investment in hospitals and schools had to be maintained.
He said the country could choose between £4bn of tax cuts from the Tories and a black hole in Labour's budget.
The need for proper public services has to be balanced with a low tax economy, Mr Howard argued.
Asked about his health policy, Mr Howard said the Tories would pay half the cost of a private operation - and the NHS would be saved that money.
He said many people who could not afford it already paid for private health care because they had to wait so long on the NHS.
The party would review whether elderly people still had to pay for personal care, Mr Howard said.
Mr Howard said the Tories' education plans were intended to promote choice, quality and standards - and they would tackle poor school discipline.
LABOUR LEADER TONY BLAIR
Tony Blair's first question was on his decision not to give the attorney general's full legal advice on the Iraq war to his Cabinet.
He responded that the attorney general had been there in person to speak to the Cabinet, and he had advised that the war was lawful.
Mr Blair said he had had to take a "tough decision" because of the urgency of the situation - but he believed it was the right decision to make.
Asked whether he went to war in Iraq simply to back the US, Mr Blair said the action had been taken for the security of the UK.
Pressed over his use of the intelligence on Iraq, Mr Blair insisted that four inquiries had found he acted in good faith.
The Prime Minister said in hindsight it would have been better to publish the intelligence on Iraq so people could judge it for themselves.
Questioned on "stealth taxes", Mr Blair said taxation in the UK was lower than in most of Europe.
He defended raising National insurance to pay for big investment in the NHS.
Mr Blair denied that extra spending on health and education was wasted, saying the improvements were visible.
Challenged about a woman's eight-month wait for a consultation, Mr Blair said he was sorry - but most people were getting a better service.
He said new cleaning regimes and matrons were helping to tackle the MRSA superbug.
The health service was not perfect but it was much better than under the Tories, Mr Blair added.
Asked about GP appointments, Mr Blair was not aware that people could often not make them in advance.
This was so GPs could meet targets on giving everyone an appointment within 48 hours, Mr Blair was told.
Mr Blair said it was something he would have to look at - because the process obviously was not working as it should.
Asked about Gordon Brown, Mr Blair said his Chancellor was focused on the economy, not on taking over as prime minister.
He said Labour must win the election before he could say whether he would vote for Mr Brown as a future leader.
Questioned on Labour's 2001 manifesto pledge not to introduce top-up fees, Mr Blair said a new, "fairer" finance system was in place.
Mr Blair was told people who had been for university "for free" should also have to pay back something.
He responded that more school leavers now went to university - and it was fairer for them to contribute to the cost than to ask all tax payers.
Asked about his leadership, Mr Blair said it was up to the voters to decide who was a good leader.
Finally pressed on why he would not debate face-to-face with Mr Kennedy and Mr Howard, Mr Blair answered that he faced Mr Howard every week in Parliament.
He argued that he wanted to answer people's questions - and felt he spoke more to people than other leaders had.