LONDON, May 22: London's mayor Ken Livingstone called for US President George W. Bush to be put on trial for war crimes in Iraq, as more than 1,000 anti-war protesters condemned the torture of Iraqi prisoners.

"There is nothing more to say than that the only way to end these horrors is by bringing our troops out of Iraq immediately," the popular socialist mayor told the rally in Trafalgar Square.

He said he hoped that Bush would no longer be immune from prosecution if he loses the US presidential election in November - after which he should be "prosecuted for the war crimes he has overseen and unleashed".

Livingstone, a regular speaker at anti-war rallies, is himself running for a second term as mayor of western Europe's biggest city in June, under the banner of Prime Minister Tony Blair's Labour party.

Blair has consistently been Bush's staunchest ally on Iraq.

Police said 1,000 to 1,200 people took part in Saturday's short march from Victoria Embankment to Trafalgar Square, called by the Stop the War Coalition in outrage over the torture of Iraqis by US troops at Abu Ghraib prison.

Several of the demonstrators wore peaked black hoods - similar to those seen in photos of Iraqis abused by US troops at Abu Ghraib - for the short march to Trafalgar Square.

Others dressed up as gun-toting British soldiers, and waved placards reading: "End the Torture. Bring the Troops Home Now!".

Rebel member of parliament George Galloway, drummed out of the Labour party in October last year for his strident anti-war views, told the crowd: "They said that they (coalition forces) were coming as liberators - and they ended as torturers."

"They said that they were bringing democracy, and instead they brought savage dogs and hoods," said Galloway, who personally knew ousted Iraqi ruler Saddam Hussein. "They said that they were bringing human rights, and instead they ended up throwing prisoners food in their toilets."

Later in the afternoon, several of the protesters moved on to nearby Downing Street, Blair's official residence.

"The American and British governments are guilty of an act of aggression," veteran socialist firebrand Tony Benn, one of the demonstrators, told Sky News television from Trafalgar Square before the rally got underway.

"They have occupied Iraq illegally," he said. "The torture is an inevitable part of the occupation."

Stop the War is best known for a million-strong demonstration through the streets of London in February 2003 against the US-led invasion of Iraq that came the following month.-AFP