The mayhem aimed at innocent shoppers and nightclubbers by Omar Khyam, Jawad Akbar, Salahuddin Amin, Waheed Mahmood and Anthony Garcia is alarming enough. But even more disturbing is the light that this terror case sheds on the operations of the security service in the months and years before the London suicide bombings on the July 7, 2005.

The day before those bombings, Dame Eliza Manningham-Buller, the head of MI5, told government whips that there was no specific threat on the horizon. Shortly before this, the terror level had been reduced from severe to substantial. That was despite July 7 being the first day of Abu Hamza’s trial and, therefore, a high-risk date. After the bombing, the public were told by the Home Secretary that the attacks came “out of the blue”. The security agencies briefed the press that the suicide bombers were “clean skins”, agency parlance for people not previously known to them.

Now we know differently. In the interests of a fair trial, for the last year the British media has been prevented from reporting that Khyam, the head of the terrorist ring convicted yesterday, was a close associate of Mohammad Sidique Khan, the 7/7 ringleader. They met on at least four occasions in England while under MI5 surveillance. We also know that they were recorded by Security Service agents talking about plans for future attacks. We now also know that Khyam met Shehzad Tanweer, another 7/7 bomber, while under MI5 surveillance. We can now also say that both Khan and Tanweer were monitored for more than a year before the suicide attack. In the case of Khan, this surveillance extended back to 2003 and more than a year before they killed 52 people, Khan was considered a “desirable suspect” by the security service.

Yet MI5 dropped the surveillance on both Khan and Tanweer, allowing them to go on to visit training camps in Pakistan, and return to commit their atrocity. MI5 claim that this was an unavoidable decision, based on the surveillance resources available to them. This prompts several questions.

First, why, years after 9/11, was the agency so starved of resources? Was the Government too slow to increase the funding after 9/11? And does it really take three years to build a surveillance team, as the Government claims? It did not take that long in Northern Ireland during the Troubles, so why does it today?

Secondly, did MI5 use its resources properly? Did it make the right decisions? Clearly, given the outcome, it was the wrong decision to take Khan off surveillance. Was that mistake avoidable?

Thirdly, did MI5, the police and Special Branch coordinate their efforts properly? We now know that Khan was followed in an identified car to Yorkshire, to clearly identified addresses. Were the local Special Branch notified, asked to check their records on the car and addresses and set up surveillance on Khan and Tanweer, which would be a normal part of their job? The Panorama programme last night suggested that this basic action was not taken. If not, why not? Is there any truth in the stories of tensions between the agencies, at a time of enhanced threat and stretched resources?

Fourthly, a photograph was taken of Khan and shown to a number of terrorists and suspected terrorists held in custody by our allies in early 2005. Yet it was not shown to the one prisoner who could have identified him before the attack. The excuse, we are told, is that it was not a very good photograph. If so, why was it circulated at all?

There may be reasons for all of these apparent errors. But public safety demands that we assess any shortcomings and put them right as a matter of urgency.

It is not even clear how much detail is known by the Intelligence and Security Committee (ISC). The people on this committee are good and patriotic MPs. But they report to the Prime Minister, not Parliament. They have no independent investigative capacity of their own – so, it is revealing that only MI5, and not Special Branch, gave the ISC evidence after the attacks of July 2005.

We need to beef up this committee, select its membership from Privy Counsellors, give it the ability to pursue its own lines of inquiry. It should be a body that keeps secrets, but at the same time holds the secret services to account.

More immediately, we need an independent inquiry into the attacks of July 7 and 21, and their implications for our security strategy. This inquiry should have a wide remit. The Prime Minister’s own unit described Operation Contest, the Government’s counter-terrorism strategy, as “immature”. It added: “Forward planning is disjointed or has yet to occur. Accountability for delivery is weak. Real world impact is seldom measured.” Yet the Government continues to use a discredited strategy that even it has no faith in.

Throughout Britain’s postwar history it was the norm for big security failures to be followed by an independent inquiry. Typically, the inquiries were led by a senior judge or Privy Counsellor. They ranged from the Radcliffe inquiry into the infiltration of British intelligence by the Soviets to the Franks inquiry into the Falklands conflict. In each case, the outcome was a public report that informed people, impartially and authoritatively, what went wrong – and forced the Government to make the required changes.

John Reid has refused to allow a “public inquiry”. We do not want a public inquiry, we want an independent inquiry, which, far from being a distraction, will be an essential tool in improving our security services. At a time when the head of MI5 has publicly cautioned that we face an unprecedented threat from 30 terrorist plots, 200 terrorist groups and 1,600 suspects, the British public – especially the bereaved and the survivors of 7/7 – deserve no less.

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