British Chancellor Gordon Brown has put the ruling Labour Party on high alert for a general election possibly next year, immediately after taking over as its new leader.

In a significant move, Brown -- who will take over as the 52nd prime minister of Britain on Wednesday from Tony Blair [Images], appointed new Deputy Labour Leader Harriet Harman as the party chairman and Transport Secretary Douglas Alexander as his general election coordinator.

In his maiden speech as the new Labour leader, Brown made it clear that the country is on the verge of a new era.

"This week marks a new start," he said. He singled out the National Health Service as his top priority, but also pledged action on housing, child poverty, education and the constitution.

"The NHS will be my immediate priority," Brown said. By contrast, Brown made only fleeting references to Iraq and Europe, or to the growing pressure he faces to deliver a referendum on the new European Union treaty agreed last Saturday by Blair.

Distancing himself from the style of Blair and Tory leader David Cameron, the new leader vowed: "I say honestly -- I am a conviction politician."

Brown formally took over from Blair as the new leader at a conference in Manchester on Sunday with the handover marked by a curt handshake between the two leaders, against the backdrop of a Union flag.

Introducing his successor at the conference platform, Blair said, "It gives me great pleasure to introduce my great friend for over 20 years, from today the leader of the Labour Party and soon to be the leader of our country."

Blair called his successor "a man with every quality to mark him out as a great prime minister."

The chancellor celebrated his appointment -- elected unopposed by the Labour Party -- with a passionate speech.

"We must have a soul," he said, pointing out his priorities.

Brown also made it clear that his Downing Street takeover will be marked by a shake-up in the government.

"I am ready to serve," he said, to a standing ovation.

"When I take office on Wednesday, I will, as our party has always done, heed and lead the call of change," he said.

With a call for a massive programme of house building and expansion of Council Housing, Brown said, "We can make affordable housing for all -- one of the great causes of our time."

A choreographed handover on Wednesday will see Blair make his last appearance at the prime minister's Question Hour in the House of Commons before heading for Buckingham Palace to tender his resignation to the Queen.

He will then retire to Chequers at Brown's invitation while work is completed in his house at Connaught Square.

Brown will follow him to the Palace an hour later and will be asked to form a government. He will then head straight for Downing Street.