Just coming down the M40 in the works van at 95mph , and i spotted a copper in one of the little "police patrol vehicles only" pull ins with a radar gun , can you still get done if there is no warning of a speed trap ahead ? as there was deffinatley no warning signs any where ,also there was no lines on the road so how can they tell which vehicle was speeding if there are 3 of you in a row ?
Could it have possibly been a tax checking gun? or dont they use them on motorways?

What sort of fine and points am i looking at if i do get done ?