These cameras (blue, either roadside or bridge mounted) are currently used to monitor traffic flow & average speed only. The technology can (and most probably will) be used to issue tickets in the future.
I have already had it on good authority (from a copper) that the newest Truvelo cameras (blue, front facing, infrared lense) are linked to these, but they currently still rely solely on the 3 white rumble strips approx 5 yrds in front of the cash machine to trigger it & issue you with a ticket. I have recently driven the A14 several times to & from Essex- it is loaded with these things, & truvellos, and I relied on braking in front of the camera down to 70mph after sitting at 100 all the way between them- I got no tickets at all.