GORDON Brown will today pick a deliberate fight with Labour left-wingers at the Brighton conference by pledging to fight the next General election on a "New Labour" platform.

The Chancellor -- almost certainly Tony Blair's successor as prime minister in 2007 or 2008 - will use his keynote speech to insist he will not abandon reform of the public services.

He will urge Labour's rank-and-file to ditch any hopes that he will swing to the left by ruling out a campaign of "old Labour versus New Conservatives".

The remarks are certain to provoke a battle with the trade unions and the party left, who hope the end of Mr Blair's premiership will signal a return to traditional Labour policies.

Yesterday, the trade unions, meeting in Brighton, denounced moves to increase private-sector involvement in schools and hospitals as privatisation by the back door.

Derek Simpson, general secretary of Amicus, warned: "If Gordon Brown follows Blair's modernisation agenda, he will lead the party to defeat at the next election."

Transport and General Workers' Union general secretary Tony Woodley said: "There is a big question mark over the party's policies and the sooner our party starts to re-engage its activists, the more likely it is that we will win a fourth term."

Dave Prentis, general secretary of Unison, said: "We don't want to go back to the Thatcher days of the market in the NHS. We want to go forward and deliver quality public services."

Over the weekend, senior Cabinet ministers indicated they expected Mr Brown to inherit the leadership, in a co-ordinated media offensive reportedly authorised by 10 Downing Street.

The move is an attempt to prevent the conference being overshadowed by rows over the timing of Mr Blair's departure - but it is seen as more important for Mr Brown to slap down the hopes of the Labour left.

In his speech, Mr Brown will share his dream of "creating in Britain a home-owning, share-owning, asset-owning, wealth-owning democ- racy, not just for some but for all".

He will say: "When commentators tell you the next election will be old Labour versus new Conservatives, tell them the truth.

"The next election must, and will be, New Labour renewed against a Conservative party today incapable of renewal.

"When they tell you that at the next election we will abandon reform, tell them that the Labour party was founded so that our values could reform Britain.

"That the great Labour governments of the last century were great because they were reforming governments that transformed Britain - and that the only future of the Labour party is as the party of reform."

Meanwhile, there was good news for Mr Blair last night when he avoided a clash over Iraq, which was not picked as one of the subjects for urgent debate this week.

But delegates will discuss the future of the health service, pensions and demands for greater powers for unions to stage strikes - all potential flashpoints.

As the conference got under way, Mr Blair was forced to deny reports that British soldiers will start withdrawing from southern Iraq as early as next May.

A Sunday newspaper claimed Britain had already "privately" informed Japan of its plans to begin withdrawal, plans to be presented to the Iraqi parliament next month.

But Mr Blair, speaking on BBC's Sunday AM, said: "What we do depends on the job being done. There is no arbitrary date that's being set and the allies are all in exactly the same position.

"Our mandate there from the UN is to stay there for as long as the Iraqi government want us and as long as it takes to build up the capability of the Iraqi forces."