Safe Speed Forums

I posted this in another section, but I have no reply. Please help. I would like to know what to do.

On Monday, while I was driving on the M4 at 1 a.m., I spotted a person in dark clothes and with a hood on top of a bridge. It had just started raining and I was driving well under the speed limit, since I am very cautious when the road is wet.
At the time it was still in my mind a conversation I had with my wife with regards to a girl who was killed by people throwing rocks down a bridge on a motorway. Once I even passed under a bridge on the M1 with children laughing and throwing stuff to the cars.

Well, I saw the guy dropping something white from the bridge and I speeded up to avoid being a target.

On the other line there was a motorbike, which was going even faster than me.

Well, before going under the bridge I saw a flash and now I have a doubt that that person was a policeman with a speedcamera. I guess he didn't aimed at the motorbike since he/she was looking at us from the front.

I didn't see any police car or any speed limit sign, so now I have a big doubt.

Was he/she a member of the police or someone else?
I accelerated because I thought I was under threat.

What should I do if I receive a speed ticket? That person induced me to accelerate due to the unusual circumstances with no signs of speed checks.

Please give me your advice. I was even thinking of reporting the event to the police.

Thank you