The statistics reported on the Guardian website today will do little to allay these concerns. Between 2001 and 2008, only 340 of 1,471 people arrested under terror legislation have been charged, of whom 196 were subsequently convicted (although it's important to note that these figures only go up to 31 March 2008, and since then there have been further convicitions in high-profile trials such as the transatlantic airline plot).
Such figures have important implications for the government's strategy for addressing the issue of homegrown extremism among British Muslims. People I spoke to in Blackburn felt that disproportionate emphasis is being placed on the issue – money, time and effort is being devoted to stopping Muslims becoming terrorists, when it should really being spent addressing genuine socio-economic difficulties. As one local community activist said to me: "The actions of four individuals on 7/7 have come to define two million people. Now everything Muslim-related is extremism-related. So if I'm sick, or my child isn't surviving childbirth, that in some way will be extremism-related? If you're a Muslim organisation looking for funding, it has to be about extremism."
If you take the actions of all those convicted, this still amounts to the actions of around 200 people (although the statistics do also include a handful of animal rights extremists) coming to define two million people in Britain. Such a high rate of release without charge will not help with the engagement work being carried out a local level in places like Blackburn, as it will only serve to increase resentment against the authorities, which in turn can only serve to benefit those looking to prey on the grievances of young people in order to radicalise them.
Of course it's a difficult one for the authorities, and those dealing with these issues in the local council and the police that I spoke to in Blackburn stressed that, since terrorist arrests have happened in the area in recent years, they have worked hard to communicate with local communities and build up a relationship of trust. Such work is indeed important, but it is also important that the police get it right when they make high-profile terror arrests. No one expects them to do so every single time, but there is a worrying gap in the statistics between arrest and convictions.