I can buy a map or electronic device that will inform me or warn me of speed cameras. The police or council authorities can put up signs warning of speed cameras but if I indicate to oncoming traffic that a speed camera is in operation i can be prosecuted for perverting the course of justice. How can I be liable when I'm doing no more than what maps signs etc. do.
Personally, I drive within the speed limit most of the time because life's too short.
However, it has been statistically proven that the proliferation of speed cameras has had **NO** impact on road casualties (the "reason" for their existance) but -oh what a surprise- MILLIONS of pounds worth of fine *revenue* has been reaped from those who were unlucky enough to be doing 35 mph+ past one.
Pervert on !
Several of the villages round our way have portable warning signs that flash when you enter the 30 limit at excessive speed. These signs are moved around the villages and are usually at a particular village for 4-6 weeks at a time, One afternoon I was on duty, carrying out a static speed check in a village and after 30 mins had not gone one speeder, so packed up and left the village. As we did so we noticed the council had put up the temp speed warning sign that morning !!