Two of the British terror suspects being held in America's high-security prison in Cuba are members of a fanatical Islamic group based in Tipton, a small West Midlands town.

The pair, named for the first time this weekend by The Sunday Times as Asif Iqbal, 20, and Shafiq Rasul, 24, flew out to Pakistan — from where they traveled to Afghanistan — within days of the September 11 attacks on America.

They are understood to have been followed by two other members of the group, who are believed still to be in Afghanistan.

All four are devout Muslims who were part of a small Islamic splinter group in the town, some of whose members are alleged to support a Muslim holy war against America. At meetings in a semi-detached Victorian house overlooking the town's park, the group — thought to number between 12 and 14 — are said by a witness to have preached that it is permissible to kill non-Muslims.

The revelations highlight the extent to which elements of Muslim society in Britain have been radicalized by Usama bin Laden's violent philosophy. They also raise questions about the ability of the police and security services adequately to monitor such groups.

Iqbal and Rasul were captured in Afghanistan before being flown, hooded and shackled with other Al Qaeda and Taliban members, to Camp X-Ray at Guantanamo Bay, Cuba. They were questioned last weekend by MI5 officers who are trying to prevent further terrorist atrocities.

Tony Blair has given assurances that the two men and a third Briton in the camp, Feroz Abbasi, 22, from Croydon, south London — whose identity was revealed by The Sunday Times last weekend — are being treated humanely.

The caged prisoners have been described by Donald Rumsfeld, the US defense secretary, as the "hardest of the hardcore" fighters captured in Afghanistan. Last week the Foreign Office phoned the parents of Iqbal and Rasul to inform them of their fate.

Iqbal's mother, Imtiaz, said the call was the first she knew of her son's role in the conflict. She said she was extremely worried he had disappeared with his "friends" a few months ago.

"I just want my son to come home," she said.

All four lived within a few hundred yards of one another and attended Tipton's Alexandra High School. After leaving, members of the group are said either to have been unemployed or done shift work.

They are believed to have been radicalized at meetings of the Islamic group, whose spiritual leader is an elderly cleric. The group is believed to have links with other radical Islamic organizations in Birmingham, Bradford and Manchester.

A senior Muslim figure in the community said there had been concern for some time about the group.

"They are hardline fundamentalists who are out of step with the majority of us, who are moderate," he said.

According to relatives, Iqbal, a night-shift factory worker, had become increasingly devout over the past three years, growing a beard and urging his family to pray more. He refused to be photographed, believing that only God has the right to make images. He paid for his own ticket to Pakistan and his mother believed he was meeting his father to prepare for an arranged marriage. His father returned, but Iqbal did not.

The two members of the Tipton group who are missing in Afghanistan have been identified by local people as Ruhal Ahmed, aged about 20, and Munir Ali, 21.

One colleague of Ali claimed he was a "nice chap" who had been brainwashed: "He used to be one of the most Westernized people I knew, but then he changed and started growing a beard. His mother is now sick with worry."