The father of a 7 July bomb victim has called for an inquiry into how MI5 failed to monitor two of the bombers.
David Foulkes had a promising career ahead of him
Graham Foulkes's son David, 22, was one of the 52 people killed when Mohammad Sidique Khan and his three accomplices blew themselves up in London in 2005.
But the MP heading the Intelligence and Security Committee said there had been "no culpable failures" in the security services over the events of 7 July.
The call for an inquiry comes after it emerged MI5 had been watching Khan.
At the trial of seven men - five of whom were found guilty - accused of a fertiliser bomb plot linked to al-Qaeda, the jury at the Old Bailey heard Khan was spotted on four occasions in 2004 with at least one of the conspirators.
MI5 officers followed Khan back to his home in Leeds but no further action was taken.
Mr Foulkes said an inquiry was needed so "lessons could be learned".
His son David, from Oldham, had just started a job as a media sales manager and was planning to start a family with his girlfriend Stephanie.
He was travelling on the Edgware Road Tube train blown up by Khan, one of four suicide bombers.
Mr Foulkes told the BBC: "The time is right for a public inquiry because we now know that the intelligence and security services have far more information about Khan and (fellow bomber Shehzad) Tanweer than they previously said.
"We now know for example that Khan was followed to terrorist training camps in Pakistan and Afghanistan as early as maybe 1999 or 2001 and we know that his phone number was associated with other recognised terrorist organisations.
"Yet on 7 July and immediately after the attacks one part of the security services were running around shouting 'clean skins, clean skins', meaning that these were home-grown terrorists and they were unable to identify them."
Mr Foulkes said it was now clear that, far from being "clean skins", Khan and Tanweer had been followed by the security services who, he said, "were well aware of their terrorist intentions and activities".
He said: "The security service is clearly disjointed and dysfunctional in that they are not talking to each other or they are not disseminating the information in a coherent way."
Mr Foulkes went further and claimed: "This left people exposed to Khan and in the intervening time nothing has changed."
He said the mixture of police, MI5, MI6 and other law enforcement agencies was a "very archaic system cobbled together from the remains of the Cold War" and was not fit to tackle terrorism.
"What we need is a coherent, single-focus anti-terrorism team who have executive authority, who talk to each other and can get something done," said Mr Foulkes.
He added: "The reality is that the current system is not working and if we do not have an independent inquiry we will just keep repeating the same mistakes."
Mr Foulkes said he had met Home Secretary John Reid, who had told him that an inquiry would not be right as it would take key people in the security services away from frontline activities.
But he said he did not accept this explanation: "The information in the public domain is just the tip of the iceberg."
Paul Murphy, chairman of the Intelligence and Security Committee (ISC), said a prior judgement by the committee - endorsing the decision that Khan should not be earmarked as a priority - still stood.
He said: "Before the July attacks, Mohammad Sidique Khan had appeared as an unidentified individual concerned with schemes involving fraud, not with schemes involving attack planning in the UK.
"As such, there were higher investigative priorities including investigations into known attack planning against the UK.
"In the committee's report into the July bombings, we concluded that this decision was understandable."
Jacqui Putnam, a survivor of the 7 July bombings, backed Mr Foulkes's call for an inquiry.
She said: "We were told by the government that the 7 July bombers were acting independently and they had no way of knowing who they were or where they came from because they were not linked to any existing terrorist organisation.
"And now we know that's not true, and in fact they did know who they were and they also knew that there were links."
She added: "We need to know why that decision was made not to take them more seriously."
Rachel North, who survived the Piccadilly Line blast, wants an independent inquiry because she said it appeared the truth had not been told about what was known about the bombers prior to the attacks.
She said: "It was tempting to believe that these guys had never been known to the police or the security services, that they had somehow managed to make these bombs and drive down to London and get on Tube trains and a bus, and that it was a terrible tragedy and there was nothing anybody could have done to stop them.
"When it transpired that was not the case, it was devastating."
Grahame Russell, whose son Philip died in the Tavistock Square bus bomb, said an apology from MI5 would not be enough.
"There should be a total public inquiry into 7 July, and I haven't changed my opinion on that," he said.
"There's still a lot more to come out, above and beyond what has been heard already."