MANCHESTER - BRITISH Prime Minister Gordon Brown used a highly personal speech on Tuesday to argue he was a serious leader for serious times in a bid to silence rebels at his Labour Party?s conference.

Mr Brown said 'the way to deal with tough times is to face them down' on the last full day of the annual meeting in Manchester, northwest England, which was dominated by talk of a leadership challenge and global economic turbulence.

'I'm not going to try to be something I'm not,' the prime minister said in a 53-minute-long speech which stressed his experience and received a warm, five-minute standing ovation.

'If people say I'm too serious, quite honestly there's a lot to be serious about ? I?m serious about doing a serious job for the people of this country.'

He also repeatedly took aim at Mr David Cameron, the youthful leader of the main opposition Conservatives who threaten to oust the centre-left Labour in the next general election, which must be held by mid-2010. 'This is no time for a novice,' Mr Brown said, pledging to provide a 'rock of stability and fairness' for the nation.

In a highly unusual step highlighting his softer side, the 57-year-old bookish Scot was introduced by his wife Sarah, who said she was 'proud' of the work her husband was doing.

Mr Brown, who was dubbed the Iron Chancellor when he oversaw a decade-long economic boom as finance minister in ex-premier Tony Blair's government, said he would do 'all it takes' to bring stability to world financial markets.

Last week's financial chaos saw the collapse of US investment bank Lehman Brothers, the nationalisation of US insurer AIG and the takeover of HBOS, Britain's biggest mortgage lender, by Lloyds TSB.

Mr Brown is battling to hold on to the job he took over from Blair just 15 months ago after four lawmakers left their junior government jobs this month and 12 called for a leadership contest against him.

A poll last Sunday put Labour 12 per cent behind the Conservatives in one of the party's better recent showings.

Mr Brown, who insisted Labour could win the next election, has united the party behind him during the conference in public, despite unceasing private talk among party insiders of whether and when he will be forced out.

Foreign Secretary David Miliband is favourite to take over if Mr Brown does go but has repeatedly stressed he is not after a leadership contest, despite reports that he wants the top job.

Speaking to AFP minutes after Brown's speech, Mr Miliband said it was 'the best speech of the week' and 'excellent'.

Asked if it would silence the critics, Mr Geoff Hoon, who is in charge of Labour discipline in parliament, said: 'I think that, assuming they listened to this speech, it was powerful, clear and demonstrated he is the man to do it.'

The speech also received a warm reception from the Labour rank-and-file including Mrs Cherie Blair's father, Mr Tony Booth, who said: 'He was short on detail but he was good on getting the people boosted, because we?re demoralised.'

But Conservative finance spokesman George Osborne insisted it showed 'the same old Brown' and contained no fresh ideas on how to tackle the challenges facing Britain.

Commentators suggested the address had earned Brown some breathing space from talk of a rebellion.

'For now it will certainly buy him time as an unchallenged leader ? at least unless the opinion polls fail to show any improvement in Labour's standing,' Sky News television political editor Adam Boulton wrote on his blog.

But he could face more threats when lawmakers return to parliament after their summer break on October 6.

He could also be damaged by a by-election in Glenrothes, the neighbouring constituency to his own north of Edinburgh, likely in November where the pro-independence Scottish National Party (SNP) could snatch the seat from Labour. -- AFP