According to the Sunday Times, the domestic intelligence agency MI5 made routine checks on Mohammad Sidique Khan as part of an investigation in 2004, but decided he was not a sufficient threat to be put under surveillance.
Police believe the 30-year-old classroom assistant was responsible for one of three bomb blasts on London underground subway trains on July 7.
The MI5 probe focused on an alleged plot to blow up a 270km truck bomb in London, an unnamed senior government official told The Sunday Times.
Britain’s Home Office had no immediate comment.
MI5 is said to have discovered in 2004 that Khan had been visiting a house used by a man who met one of the suspected plotters, but decided that as he was “indirectly linked” to the affair he posed no risk.
“We’ve only got finite resources. You can only concentrate resources on those people who are a direct threat to national security,” the official told the paper.
Police and intelligence services had previously insisted that none of the four suspected bombers had previously known links with terrorism.
With the suspected bombers dead, the massive police investigation is largely focusing on who might have helped the men plan the attack and build their rucksack-borne bombs.
The hunt has spread around four continents, with considerable focus placed on Pakistan, from where the families of three of the four suspected bombers originated.
ISRAEL ATTACKS: On Sunday, the Israeli newspaper Maariv claimed that Khan had additionally gone to Israel two years ago to help plan a suicide attack in Tel Aviv.
According to the paper, Khan is suspected of organizing the bombing in a Tel Aviv pub in 2003 in which three people were killed.
The final London bomber has been named by police as 19-year-old Germaine Lindsay, a Jamaican-born Muslim convert.
According to British diplomats in Jamaica, Lindsay’s father Nigel, 45, had been interviewed by local police at the request of London officers.
A further strand of the investigation is in Egypt, where Magdy Mahmud Mustafa Nashar, formerly a doctoral student in chemistry in Leeds, was arrested on Thursday.—AFP