The following is from Sky News -
http://www.sky.com/skynews/article/0,,30100-13528827,00.html
It seems that the "information" alerting police / MI5/6 to the recent terror raids came from a prisoners who had a lower than average IQ of 69 (slightly higher than the average police officer, then?)
The brothers were put under serveillance after they visited the "informant" in prison.
So ... merely visiting someone (who has yet to be convicted of anything) these days gets you branded a terrorist does it?