Maybe you've all seen this already, but I just came across this and thought it was interesting:
http://www.craigmurray.co.uk/archives/2006/08/the_uk_terror_p.html--snip--
"None of the alleged terrorists had made a bomb. None had bought a plane ticket. Many did not even have passports, which given the efficiency of the UK Passport Agency would mean they couldn't be a plane bomber for quite some time.
In the absence of bombs and airline tickets, and in many cases passports, it could be pretty difficult to convince a jury beyond reasonable doubt that individuals intended to go through with suicide bombings, whatever rash stuff they may have bragged in internet chat rooms.
...
We will now never know if any of those arrested would have gone on to make a bomb or buy a plane ticket. Most of them do not fit the "Loner" profile you would expect - a tiny percentage of suicide bombers have happy marriages and young children. As they were all under surveillance, and certainly would have been on airport watch lists, there could have been little danger in letting them proceed closer to maturity - that is certainly what we would have done with the IRA.
In all of this, the one thing of which I am certain is that the timing is deeply political. This is more propaganda than plot. Of the over one thousand British Muslims arrested under anti-terrorist legislation, only twelve per cent are ever charged with anything. That is simply harrassment of Muslims on an appalling scale. Of those charged, 80% are acquitted. Most of the very few - just over two per cent of arrests - who are convicted, are not convicted of anything to do terrorism, but of some minor offence the Police happened upon while trawling through the wreck of the lives they had shattered.
Be sceptical. Be very, very sceptical."