The security services have been given the resources they need to tackle terrorism in the UK but can only expand at a certain rate, John Reid insisted today.
The home secretary was responding to a parliamentary committee report on the London bombings of July 7th, which said the failure to stop the bombers was due primarily to a lack of resources to deal with the knowledge available.
In a statement to the House of Commons this lunchtime, he also ruled out a public inquiry into the bombings, citing his predecessor's argument that it would be too much of a distraction.
Although Mr Reid has accepted most of the report, he insisted that the security services were expanding as fast as was "organisationally possible" and that their funding had increased in the wake of the September 11th attacks in New York.
By 2007-08, he continued, the police budget for counter terrorism would have increased fourfold from what it was in 2002, while Special Branch was getting an extra £30 million next year and £60 million the following year to expand its operations beyond London.
However, shadow home secretary David Davis warned that the revelation that two of the London bombers, Sidique Khan and Shazad Tanweer, were known to security services before July 7th but not pursued showed a clear - and dangerous - lack of resources.
"Is it the case that there were not enough MI5 agents to cover the possible suspects, and that this led to surveillance on dangerous terrorists being terminated too soon?" he asked.
"The ISC report says that 'better appreciation of the speed and scale with which the threat against the UK could develop might have led the services to achieve a step change in capacity earlier'.
"Did this occur because the resources for MI5 were not increased by the necessary step change until 2004, three years after September 11th? And because it takes three years to recruit, screen and train agents, this expansion will not take full effect until 2008?"
The only way to resolve these questions was through a public inquiry, he insisted - today's committee report was necessarily limited because it depended on information provided by the security services themselves.
But Mr Reid rejected this, and also noted the difficulty in tackling the kind of home-grown terrorism responsible for last summer's attacks.
The Home Office's account of the events of that day, also published today, showed the four bombers were "ordinary British citizens with little known history of extremist views, far less violent intentions", he said.
There was no mastermind in the plot, they used everyday objects to make their explosives, and their radicalisation was conducted "away from places with any obvious association with extremism", Mr Reid noted.
Whatever the level of resources, "difficult choices have to be made between priorities in intelligence-led operations", he added, while the bombers' willingness to take their own lives and hit a civilian target made them "doubly difficult to defend against".
As a result, while the home secretary noted that three terrorist attacks in the UK had been thwarted since July 7th, as proof that the security forces were doing their job, he insisted: "International terrorism will not be defeated by the security service alone.
"Nor the police alone - nor the government alone. But only by all of us in this country working together to defeat this threat to us all and that is something we must all work together to achieve."