Saw them flash a few times between jct10 and the M4 going to Nottingham the variable sign was on for 50mph and a number of cars went past us faster and were flashed,obviously dont know if they got a ticket.
Dont know how true it is but I am sure somebody will say whether it is but my son says that the cameras only work where and when the variable limit signs are on or if there are road works with an average speed limit.
According to my son the cameras only work when the variable speed limit sign is shown on the M25 but did notice going to Nottingham on Saturday that they flashed in front of us a few times when cars sped through the signs, hence son stuck to the limit when they were on