British security services secretly followed the four bombers who killed 52 people on London's transport network a year before the July 7th attacks, the Daily Mirrornewspaper reported this morning.
Intelligence officers ended the surveillance operation, which ran for several weeks, after deciding the men posed no threat, the newspaper said, citing an unnamed police source.
The four young Britons went on to detonate homemade bombs concealed in rucksacks on three underground trains and a bus at about 9am on July 7th.
The men - Germaine Lindsay, Shehzad Tanweer, Hasib Hussain and Mohammed Sidique Khan - were on a list of 100 suspected extremists in Britain, the Mirrorreported.
The BBC said last month that officials secretly filmed Khan during a 2004 surveillance operation. It was unclear if it was during the same inquiry as the one outlined by the Daily Mirror.
A London police spokeswoman declined to comment, and the Home Office could not be reached for comment.
