One of the trustees of a London [Images] mosque has said that he warned police in 2003 about a group of extremists including a suspected July 21 subway bomber.

Toaha Qureshi, a trustee of the Stockwell Mosque in south London, said Hamdi Issac, also known as Osman Hussain, was among a group reported to police for 'inciting racial and religious hatred in the community' and intimidating mosque management.

"They have an agenda to turn this centre into another Finsbury Park Mosque," mosque leaders said in a July 2003 letter, referring to the north London mosque that was a hotbed of radical preaching and was closed down by authorities earlier that year.

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Police provided a more visible presence in the area after the letter, but took no action against the group, Qureshi said. He said the extremists were eventually expelled by mosque management.

"We could not have been more explicit. It was put in such a manner that it should have been taken seriously," Qureshi said. "If they had done something then I don't know how many lives we could have saved."

The Metropolitan Police said it considered all correspondence it received confidential and could not comment.

The force said police maintained 'regular close liaison' with representatives of all the mosques in the area. "If and when concerns are expressed, prompt action is taken to address those concerns," the police said in a statement.

Issac, 27, is suspected of trying to bomb a west London subway station on July 21. He fled Britain after the attacks and was arrested in Rome.