Charles Kennedy called for a second UN resolution

At the party's spring conference in Torquay, Devon, Mr Kennedy told his party they were acting with "consistency of principle and sincerity of purpose".

Opening an emergency debate on Iraq, he called for the UN weapons inspectors to be given more time to carry out their task.

He also called for a second UN resolution before any action went ahead, saying doing without it "undermines the authority and legitimacy of the United Nations itself."

But he said if British troops were sent into battle, he would "fully support" them.

We put the weapons inspectors in, we asked them to do a job, they have come back and said they are making process on a peaceful basis towards disarmament but they need more time Charles Kennedy

At the end of the debate there was overwhelming support for Mr Kennedy's position, with just a handful of people voting against him, said the BBC's Sean Curran, at the conference.

Mr Kennedy has been called an "appeaser" and an "opportunist" in the Commons, after marketing himself as the only leader of the three main parties opposed to war.

But he insisted his stance was principled and reasoned.

"There is nothing opportunistic about our stance whatsoever," he told Sky News ahead of the conference.

He later predicted public opinion would not suddenly swing behind war when troops were sent in to battle.

"Even if it is a swift and relatively humanitarian war - and that is a big if - there will be no triumphalism," he said.

"There are genuine divisions in the country. I think a lot of people will remain unpersuaded, although backing our forces."

The BBC's Sean Curran said Mr Kennedy was treading an extremely fine political line.

Support for troops

He said: "If there isn't a second resolution, and there's a vote in the Commons, then his party would vote against the government.

"However, if that vote or any debate was to happen after British troops were in action, then his party would not vote against the government.

"He's going to abide by a parliamentary convention which says that once British forces are engaged, then Parliament is there to show its support for the troops.

"That doesn't mean they won't ask political questions, but the Liberal Democrats are very concerned this morning that they're... also reaffirming their support for the British troops that are already out there."

Opportunist. Appeaser. Loser. Click here for a Commons' view of Charles Kennedy

Also at the conference, Lib Dem Treasury spokesman Matthew Taylor has set out the party's tax-and-spend plans.

He reiterated the party's pledge to cut �100 from every household's council tax bill.

And he said the Lib Dems would scrap the "highly regressive" council tax and replace it with a local income tax.

Mr Kennedy called on Lib Dems to give a "harder edge" to their policy on the euro by adopting conditions on entry in a vote during the afternoon.

Delegates were voting on a paper which proposes changes to European Central Bank - calling for more independent members, published minutes of interest rate decisions, an inflation target of 2% or 2.5% and changes to the rules on member countries borrowing.

Later in the day home affairs spokesman Simon Hughes will talk about asylum, criticising both Labour and the Conservatives for failing to come up with real solutions.

He is also expected to repeat attacks on Home Secretary David Blunkett's treatment of the courts and legal system.