The law states - "31.2 The operator must be clearly visible to the public and the target vehicle throughout the check."
Manned speed traps have to be in full view of on coming traffic. The police vehicle and their Hi-Vis jackets also have to be in full view too. This person is only police staff and not an actual policeman. He was hiding and obscuring himself in view of on coming traffic. Location - Chard High Street, Somerset, England. (3.45pm, 4 May 2016 {50.87261 -2.97193}) Thankfully, I didn't get caught speeding as I always drive slow in that area, but he must have caught hundreds of non locals as just about everyone is slightly over the speed limit due to the sloping hill into the town.

I made this video because a manned speed trap is not allowed to be hidden like that. The speed gun lens was pointing over a telephone junction box and the person was obscured behind it too.