British troops used six tanks to break into a prison in the Iraqi city of Basra to breakout two 'soldiers' arrested by Iraqi police.

“A large force of British troops surrounded the police building, smashed down the main entrance with a vehicle, and freed the two Britons along with 150 prisoners,” an Iraqi defence official reported.

Britain’s Defence Secretary John Reid and the British embassy in Baghdad have confirmed that two British soldiers have been “released” from detention.

An Iraqi interior ministry official said that the two Britons had been involved in some kind of 'undercover' operation, a claim that has been neither confirmed nor denied by British military officials.

Driving in a civilian car, the pair were said to be wearing traditional Arab headdresses and clothing. Mohammed al-Badi, an official with the Basra governor’s office, said the two men had appeared suspicious to police.

“A policeman approached them and then one of these guys fired at him.” Mr Abadi said.

The Brits were arrested and charged with shooting two Iraqi policemen - one of whom was killed at the scene. Some sources have reported that explosives were found in the car driven by the captured Brits.

Arab satellite television networks broadcast photos of two Western men, identified only as Britons, seated on the floor of the jail, one with a bandage covering most of the top of his head and the other with blood on his clothes.

“We can confirm that a shooting incident involving UK military personnel has taken place which is currently being investigated,” a British military spokesman said in a statement.

Later, the presence of British armoured units outside the prison ,where the two spys were being detained, sparked violent protests. Petrol bombs, burning furniture and tyres and stones were hurled at the troops and tanks, two of which were abandoned by fleeing British soldiers. At one point, a British soldier was seen fleeing from a tank, his body covered in flames.

Two Iraqis were killed as the British occupiers retaliated and later stormed the prison to help the spys escape justice.