BRITISH troops in Basra were placed on alert last night after it was confirmed that Saddam Hussein's hated henchman Ali Hassan al-Majid - dubbed "Chemical Ali" - has been captured.

US Central Command said that al-Majid, number five on America's most wanted list, was seized on Sunday in the company of his bodyguards.

Last night, troops were bracing themselves for hundreds of armed Iraqi's taking to the streets of Basra to celebrate the demise of a man who ordered the use of chemical weapons dozens of times and killed more than 100,000 people in sadistic purges.

A first cousin of Saddam Hussein, he was one of his most trusted and feared aides who organised the defence of southern Iraq from his intelligence headquarters close to the city.

US military officials will have almost certainly sought to question him about the whereabouts of the former dictator who is still being hunted by US and British troops.

News of his capture had come as a welcome boost to the British troops of 19 Mechanised Brigade.

The soldiers, who took over from the Desert Rats once the fighting ended, have been placed on alert in the city where Chemical Ali was branded the "Butcher of Basra".

Troops have also been warned to watch out for stray bullets fired from the rifles of jubilant Iraqis.

No further details of his arrest were immediately available last night, but In London his capture was welcomed by the Foreign Office.

A spokesman said: "People who may be responsible for crimes in relation to the Saddam Hussein regime should be arrested and brought to justice."

The one-time leader of Saddam's secret police, the Mukhabarat, he faces certain trial for war crimes.

He ordered the infamous gassing of the Kurds at Halabja in 1988, which killed 5,000 and also led brutal purges in the north, which left more than 100,000 dead.

He authorised the looting, pillaging and torture of Kuwaitis during the 1990 invasion and led the mass executions to repress the 1991 uprisings by the southern Shias in Basra.

British military sources had claimed that al-Majid was killed in a bombing raid on Basra in April.

However, in June, General Richard Myers, the chairman of the US Joint Chiefs of Staff, disclosed that Iraqi prisoners had indicated that he may be alive.

Al-Majid's former palace close to Basra was looted by the people he was sent to govern in the wake of April's precision-bombing raid.

Among the debris of the Moorish-style building - which boasted a 25ft swimming pool and smoked glass windows and chandeliers - troops found syringes carrying biohazard warnings, labelled as arterial blood samplers.