Mr Clegg said he would not "condemn" UK forces to failure

The Liberal Democrats could stop supporting the UK's military presence in Afghanistan unless strategy is changed, leader Nick Clegg said.

He told BBC One's Politics show he wanted the mission to succeed but the present course was "almost certainly condemned to failure"".

Mr Clegg also said his party's backing for the war was not "unconditional".

The comments come after Prime Minister Gordon Brown pledged to send another 500 troops to Afghanistan.

There are currently about 9,000 UK military personnel in the country, while some 221 have been killed there since 2001.

'Heads held high'

The US government is debating a request for 40,000 more troops in Afghanistan.

Mr Clegg said: "Clearly no support that any political party gives for a conflict, for a war, is unconditional."

He also said: "The present strategy is failing so it needs to be changed and the discussions which are taking place in Washington at the moment are immensely important in working out whether we have got a strategy which will succeed.

"If that strategy, if that new strategy is, in our judgement, the wrong strategy, which will condemn our soldiers to failure, then of course we will revisit our support, of course."

He told Politics Show: "I think if we carry on, on the present course, we are almost certainly condemned to failure. I want us to succeed in Afghanistan."

"I want - when our servicemen and servicewoman leave Afghanistan - I want them to leave with their heads held high, feeling they've done a good job, a successful job, done what we're asking them to do not with a tail between their legs."

The SNP said Alex Salmond had the right to be included as a party leader

The SNP may take legal action if Alex Salmond is not allowed to take part in a UK party leader TV debate ahead of the next General Election.

The BBC, ITV and BSkyB jointly proposed three live debates between the Labour, Tory and Liberal Democrat leaders.

SNP Finance Secretary John Swinney said going to court was not being ruled out, but said it was more preferable to come to an agreement with the broadcasters.

Opposition parties accused the SNP of bullying tactics.

Tory leader David Cameron and Liberal Democrat leader Nick Clegg have welcomed a TV debate, while Gordon Brown has now said he was willing "in principle" to take part.

Mr Cameron has told the BBC he wants a respected independent figure to oversee the negotiations for the TV debates.

'Depriving voters'

But the SNP has threatened to seek to block the screening in Scotland of any debate which did not include Scottish First Minister Mr Salmond.

Mr Swinney told BBC Scotland's Politics show the SNP was the party of government at Holyrood, adding that the UK debates would discuss issues of importance to Scotland, such as the future of nuclear submarines on the Clyde.

Mr Swinney said the SNP was prepared to be flexible, saying of the current arrangements: "It deprives the voters in Scotland of hearing the breadth of political choice that quite clearly exists here in Scotland about the input of Scotland into the UK General Election."

Current plans would see the three main UK party leaders take part

On the issue of legal action, he added: "That might be a possibility, but, long before we get to that judgement, we have to have full and open discussions with the broadcasters about the arrangements that can be put in place."

Also speaking on the programme, shadow Scottish secretary David Mundell said it was not appropriate for Mr Salmond to take part in a debate about who should be the prime minister of Britain.

Labour described the SNP's option of going to court as a "sinister threat", and claimed, along with the Liberal Democrats, the Nationalists were attempting to bully broadcasters.

The broadcasters have said they would each seek "to make suitable arrangements for ensuring due impartiality across the UK", but have not yet explained how that would be achieved.

The Lib Dem leader was bidding to reassert his authority after a bruising week - and reach out to disaffected Labour voters thinking of voting Tory.

In his speech he urged voters not to sleepwalk into a Tory government and opt for "real change" instead.

The Lib Dems say their private polling shows the next election is "wide open".

Mr Clegg spoke without notes for just under 50 minutes - and his speech was greeted with a standing ovation from delegates in the Bournemouth centre, which included wife Miriam and former party leaders Lord Ashdown and Sir Menzies Campbell in the front row.

Labour 'dying'

The speech was also watched by a group of Gurkhas, who received a round of applause after Mr Clegg said he was "honoured" they could be present.

I want to be prime minister because I have spent half my lifetime imagining a better society Nick Clegg, Lib Dem leader As it happened: Clegg speech Send us your comments Analysis: Clegg's proposal to voters

Mr Clegg deliberately chose not to talk about what might happen in the event of a hung Parliament, focusing instead on what a Liberal Democrat government would do.

He stressed the party's commitment to fairer taxation and vowed to "clean up" Westminster politics including MPs' expenses.

And he said young people were his party's top priority - and proposed a 90 day job or training guarantee for the young unemployed, paid for by scrapping Labour's VAT cut.

He said: "Labour is dying on its feet. We are replacing them as the dominant force of progressive politics. We are the alternative to a hollow Conservative Party that offers just an illusion of change."

'Mansion tax'

He began the speech by hardening his line on Afghanistan - saying there was "one more chance to turn things around".

"I know some of you believe we should call for British troops to withdraw now," he told delegates.

"If things continue on the present disastrous course, then sooner or later that is a judgement which we may need to make."

But there was no mention of dropping a pledge to scrap university tuition fees from the next manifesto - a suggestion which sparked open warfare in the party at the start of the week.

He briefly mentioned Vince Cable's £1m "mansion tax" in a section on rebalancing the tax system so that the wealthy pay more.

The 0.5% levy on owners of £1m-plus homes sparked a backlash from some of the party's senior MPs earlier in the week, prompting an admission from the Treasury spokesman that he could have consulted more widely before announcing it.

'Progressive austerity'

Mr Clegg also addressed criticism from former leader Charles Kennedy, who said the party was in danger of losing its "heart" with Mr Clegg's talk of the need for "savage" spending cuts to tackle Britain's record debts.

Unlike Labour and the Tories, the Lib Dems had "come clean" about what cuts were needed and were guided by principles of "fairness", he said.

"Not just austerity, but progressive austerity. Reducing the deficit, yes, but also building a fair society and a green economy.

LIB DEM CONFERENCE TWEETS Twitter: @BBCLauraK That's it from Bournemouth - conference set being broken up at great speed! More from Labour in Brighton from Saturday #ldconf 14 minutes ago Some activists say Clegg 'exhilarating' -some unimpressed-leaving conference not clear what they'll be able to punt on the doorstep #ldconf 51 minutes ago Evan Harris,sometime Clegg critic,says speech was 'great not good' #ldconf About 1 hour ago Audience seem quite happy but loudest applause was for Iraq-more confident than last year-hugging gurkhas now About 1 hour ago Clegg's eldest son has already written to Santa-but not many goodies so far for activists in speech-they like tax plans though #ldconf About 1 hour ago What is this?

"Still driven by generosity of spirit, but fit for the circumstances of the day. It's the only way to deliver real change in Britain."

He spoke at length about what Britain would be like if the Lib Dems were in power, in what aides described beforehand as the most ambitious speech ever given by a leader of their party.

"I want to be prime minister because I have spent half my lifetime imagining a better society. And I want to spend the next half making it happen," he told the party faithful.

Mr Clegg ended by delivering a message to voters who do not usually vote Lib Dem or have given up voting altogether, telling them: "Don't stay at home, don't vote Conservative just because you think it's the only option."

He said: "If you supported Labour in 1997 because you wanted fairness, you wanted young people to flourish, you wanted political reform, you wanted the environment protected, or you simply believed in a better future, turn to the Liberal Democrats.

"I know there are people who agree with a lot of what we've got to say, but who still don't vote Liberal Democrat. You don't think we're contenders. I urge you to think again."

Mr Clegg's predecessor as party leader Sir Menzies Campbell hailed the speech as "an extremely impressive performance" which showed Mr Clegg was "ambitious for the party and the country".

He said the speech was "uncompromising" in spelling out the difficult decisions that needed to be taken and it showed Mr Clegg was "leading from the front". He compared Mr Clegg's call for change to US President Barack Obama's message.

But Conservative Party chairman Eric Pickles, giving his reaction to the speech, said:"Nick Clegg says he wants to be prime minister but I listened to his speech and still can't discover a reason for voters to choose him over David Cameron.

"After this muddled conference, it's now clearer than ever that if you want to get rid of Gordon Brown and his big brother state, and if you care about our schools, our quality of life and our liberties, you need to vote Conservative for a progressive, liberal government."

Liberal Democrat leader Nick Clegg has set out plans to "cut the cost of politics" by nearly £2bn.

His plans include closing 10 government departments and 90 quangos, axing spin doctors and no longer paying Opposition leader's wages out of the public purse.

Speaking on the second day of his party's conference, Mr Clegg said: "Central government in Whitehall is too big, too powerful and too expensive."

The £2bn savings would be enough to renovate 200 schools a year, he said.

Cutting the cost of politics is one of the key themes of Tory leader David Cameron who has said he would cut ministerial salaries and reduce the number of MPs, as well as slashing quangos.

Labour has also vowed to squeeze Whitehall spending.

Mr Clegg is using what will be his party's final conference before a general election to emphasise the need for what he has called "savage" public spending cuts - although he toned this down to "serious" cuts in a speech to party activists on Saturday evening.

Spin doctors

He risked the wrath of his party's left wing in the speech by saying he may be forced to drop its long-standing commitment to free university tuition.

But his proposals to cut the cost of politics are likely to go down better with the party faithful.

Mr Clegg says he would freeze ministers' salaries and cut the number of them on the government payroll from more than 100 to 73.

He would also halve the number of departmental spin doctors.

He told BBC News: "We could save billions by scrapping entire government departments and culling quangos.

"Doing politics differently and saving money means dismantling Labour's spin machine by halving the number of government press officers and making political parties pay for their own special advisers.

"The nearly £2bn savings in our proposals could be invested in public services and would be enough to renovate 200 schools every year."

Pay cap

The Liberal Democrats went into the 2005 election promising to close eight government departments, including what was then the Department of Trade and Industry, but the latest proposals go slightly further.

Mr Clegg says he wants to cut the number of government departments from 24 to 14.

He also published a list of quangos he wants to see culled.

These include regional development agencies - a long-standing policy commitment - but also less well-known bodies such as the School Food Trust, Teachers TV, the Independent Advisory Group on Teenage Pregnancy, the Civil Nuclear Constabulary and the Covent Garden Market Authority.

The document also proposes a reduction in the budget of the Serious and Organised Crime Agency.

Health spokesman Norman Lamb will also call for quango chiefs' pay to be capped at the same rate as the prime minister's.

In a keynote conference speech he will promise to cut the size of the Department of Health by half and to scrap strategic health authorities.

The party says it would save £500m by reducing health quangos.

Mr Lamb will claim health quangos alone now cost around £1.2bn a year and employ 25,000 people - and that 24 of their chief executives are paid more than Gordon Brown.

Mr Lamb wants to give ward sisters more control over their budgets and greater responsibility for the staff who work with them.

He will also propose recruiting 3,000 more midwives and health visitors to tackle the current shortfall.