The Foreign and Commonwealth Office confirmed yesterday that the two British citizens — and possibly a third whose identity is still being checked — had been captured last year and were being held as suspects under military detention.

The first was arrested by British troops in November in southern Iraq and is being held at the Shaibah military camp near Basra on the ground that he poses “an imperative threat to security”.

The second suspect was seized by US Marines last month and is being held at Abu Ghraib prison outside Baghdad. The men are part of a growing number of more than 300 foreigners captured in Iraq and suspected of volunteering to fight for the insurgency. Most come from Arab countries such as Saudi Arabia, Syria and Yemen but Muslims from Britain, France and other Western countries have also been caught up the conflict. Foreign fighters, in some cases working for Abu Musab al-Zarqawi, the Jordanian terrorist mastermind, have often been used for the daily suicide attacks in Iraq.

The Foreign Office refused to release the Britons’ names or where they came from, saying that their families did not want their identities revealed. Both are believed to be British Muslims of Asian origin.

The detainee held by the Americans is thought to be 25 years old, born in Pakistan but with a British passport. His American captors said that he spoke with a British accent.

He was arrested on December 7 in the rebel stronghold of Ramadi by a patrol of US Marines who allegedly surprised a group of insurgents passing Kalashnikov rifles over a wall between two houses.

A brief gunfight is said to have broken out and the Americans then arrested several suspects, including the young Briton. He told his captors that he was a peace worker and had come to Iraq to help the civilian population. He denied that he was involved in the violence directed at American forces and the US-backed Government in Baghdad.

Although he was unarmed when captured, the Americans said that a test on his hands revealed traces of explosives.

When questioned about this, he allegedly explained that he had found a pile of weapons on his bed where he was staying. He had moved them in order to get to sleep and his hands had probably been contaminated with residue. He was held for several days at the base in Ramadi, where a correspondent for The Economist reported that US troops were glad to find a prisoner who spoke English so that they could taunt him.

The Americans did not believe his alibi and he was sent to Abu Ghraib, where last year US forces were accused of torturing Iraqi prisoners. The British Embassy in Baghdad has been in touch with the US military authorities over the case and a consular official is expected to visit the prisoner “very shortly”.

Lieutenant-Colonel Barry Johnson, the US deputy responsible for detainees in Iraq, said yesterday that the Briton’s case would be reviewed within 90 days when he would either be released or kept in custody if he continued to pose a security risk. “He will be given exactly the same procedure as other detainees, whether Iraqi citi-zens or third-country nationals,” Colonel Johnson said.

A spokesman for the Ministry of Defence in London refused to give any details about the British suspect being held in southern Iraq, other than to confirm that he was detained in November.

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