In an interview with BBC World's HARDtalk, Mr Ashdown said he continued to support Nato and the UK Government.

"We have to grit our teeth and see this through," he said.

Mr Ashdown has always supported the use of ground troops to make it safe for refugees to return to Kosovo. He said Nato's victory depended on it.

Paddy Ashdown: "The cohesion of Nato today is stronger than it was at the start of the campaign"

"The idea that you can bomb Milosevic into submission has always seemed to me to be a fanciful one. I hope it works.

"He's winning and we're not.

"And what that means is, when we do what needs to be done in Kosovo, unless we do more to degrade, to bring down the quality of the Serb forces in Kosovo we're not going to be able to do it."

Tears at refugee crisis

Mr Ashdown is a former Royal Marine and has made 14 visits to the Balkans in times of war - during the current conflict with Serbia and during the Bosnian war.

In his most recent visit to a refugee camp in Macedonia, he openly cried at the scenes he witnessed.

Paddy Ashdown has visited the Balkans many times

He told HARDtalk's Tim Sebastian: "If those refugees don't go back then we have no victory.

"If we are to use ground troops we need to take a decision in the next two weeks.

"If we don't take a decision in the next two weeks we are not going to get a ground troop victory.

"And as I said to the prime minister when I asked him this question, our will to use ground troops will determine whether or not at the end of this it's victory or compromise.

"There can be victory or there can be compromise, and you can only get victory if you're prepared to put in ground troops in. Otherwise it's compromise. And we've got two weeks to make that decision."

Prime Minister Tony Blair has ruled out sending in ground troops, though there is speculation that he is on the verge of changing his mind. Conservative leader William Hague joined Paddy Ashdown on Wednesday in calling for a such a force.

Paddy Ashdown: "Hypocritical to say the least"

But Mr Ashdown said he was angered at the shift in Conservative policy over the conflict.

"The Conservatives have been disgraceful on this, they've been all over the place," he said. "They have the right to criticise but we can expect them to be consistent.

"And they were against ground troops to start with, indeed they were very iffy about whether they'd support the whole thing."

Future ambitions

Mr Ashdown has just a few weeks left as Liberal Democrat leader. In January he announced his intention to step down after the European Parliament elections in June.

He said: "I wanted to leave space in my life to do something else. This is a young man's job, you need a young man's energy."

He hinted he might like to get involved in some kind of foreign affairs work and said he would like to write more books.

One thing was certain though: "If you think the next thing is pipe and slippers forget it."

You can watch the HARDtalk interview in full on BBC World and News 24 at the times shown below.

BBC World (times shown in GMT)
May 13 0930, 1530 and 1930