M25 speed cameras or traffic management cameras

After leaving Alderstead Heath CC site travelling east bound I came across the M25 shut due to an accident on the section at Clackett Lane that leads up to the Dartford crossing Junction 5.The two nearside lanes were shut with the arrows on the matrix boards moving you over to lanes three and four, but crawling in these two shut lanes ,(I was in lane two now) I could clearly see the speed camera's behind me activating in my tow car's mirrors.With four lanes crawling at walking pace (matrix boards set at 40mph)were they activated because of driving in these shut lanes?