The first detailed accounts of the July 7 bombings have cleared the intelligence services of any failings in not preventing Britain's worst-ever terrorist strike.
But at the same time the reports, one by an influential parliamentary committee and another by the Home Office, highlight the magnitude of the task they face in foiling such plots.
Four British Muslim extremists killed 52 innocent people and injured more than 700 others when they blew up three London Underground trains and a double decker bus during the morning rush hour by detonating bombs packed into rucksacks.
Two of the men, Mohammad Sidique Khan, 30, and Shehzad Tanweer, 22, had appeared only vaguely on Britain's intelligence radar beforehand.
They were considered peripheral figures at the time and were not pursued, with agents preoccupied with "more pressing priorities", the parliamentary Intelligence and Security Committee said in its 44-page report.
Pakistan link
After the bombings, it emerged the bombers had been to Pakistan. Khan visited in 2003 and again, this time with Tanweer, between November 2004 and February 2005.
"It has not yet been established who they met in Pakistan but it is assessed as likely that they had some contact with al-Qaeda figures," the report said -comments echoed in the Home Office document.
The two men, whose identities were established only after July 7, probably received "operational training" there, it said.
For his part, British Home Secretary John Reid said there was no "irrefutable evidence" that the terrorist group played a part in July 7.
"However, there is considerable circumstantial evidence which runs from the fact that Khan visited certainly Pakistan, possibly outside it, and that he went back (there) with Tanweer between November and February 2004 to 2005," he said.
Despite any prior suspicions, the parliamentary committee's chairman, Paul Murphy, said the intelligence services were not to blame.
"There was no culpable evidence of failure on the part of the agencies," he said. "Our view is that it was understandable that the leads were not taken any further."
The report identified the lack of resources available to the security agencies, mainly Britain's domestic spy service MI5, as one of the main reasons why they failed to prevent the attacks.
At the same time, the committee dismissed theories which circulated after the attacks of a fifth bomber or "mastermind" who may have subsequently fled the country.
It also said the intelligence agencies found no evidence of direct links between the July 7 attacks and a botched attempt apparently to replicate the bombings two weeks later on July 21.
The 37-page Home Office report gave greater details on the attack - which cost less than ₤8,000 (A$19,321.34) to pull off - summarised the findings of the ongoing investigation and explored the motivation of the bombers.
Both reports, launched last year after the government ruled out a public inquiry, looked at the radicalisation of Britons and how hard it was to spot.
Three of the July 7 gang - Khan, Tanweer and Hussain - were British-born Muslims of Pakistani origin, while Lindsay was a naturalised Briton from Jamaica.
Families unhappy
Despite the extensive, detailed accounts of what happened, families of the victims reiterated their demands for a public inquiry.
They also rejected the suggestion a lack of resources was to blame.
Nader Mozakka, 50, whose wife Behnaz died in one of the underground train blasts, said the reports had produced "useless information".
"The government is running scared of doing anything that might go down badly with the Muslim community," he said.
"At the same time, people are being radicalised left, right and centre."
Stephen Vaughan was a close friend of Sam Badham and her partner Lee Harris, who were also killed in the blast at Russell Square.
"Probably the most important thing is that we need to help the Muslim community to find out where religious extremism emerges from and why it emerges so that we can all tackle it," he said.
"We want to know where this came from in detail so that those communities can work to stop this sort of thing happening again."
Daniel Biddle, 27, lost his legs and an eye in the Edgware Road bombing and is still receiving hospital treatment.
"To do a report a year on, it doesn't help anybody. To turn round and say no one was at fault, it doesn't help the survivor to get past it," he told BBC News.
"To me, there's no justice because the person who's at fault killed himself when he set the bomb off.
"I can't get a sense of justice from any report. It doesn't enable me to move on."