Flashed by camera on M1 last night

[Spanglepants]

First off, I broke the law and got caught - so no complaints
Last night returning from London going northbound i was behind a Mercedes in the outside lane , as we both passed cars in the middle lane he pulled over and i accelerated past. This happened, as best i can remember, going under a bridge just before Junction 12.
Im certain my speed at that point was high 80s - fair enough. Im curious though as to why it went off when I passed but not for other traffic ? I know there were cars ahead of me that had overtaken at a much higher speed.
So whats the likely outcome? Last time I got done for speeding was 1985 - 3 points and £50.

[Spanglepants]

There were no speed limits signs on, I think that is why I was surprised. No excuse but after the driving i'd seen up to that point I was watching the Mercedes rather than looking for cameras.

O/T
I saw countless cars just sitting in the middle lane with no other cars anywhere near them ( empty lanes ahead and behind) and saw one car, again with no traffic in front of him/her move from the inside lane to the middle??

[Spanglepants]

Thanks, fingers crossed and I'll try not to think about it.
I only went to London with my son to get away for a bit as I've not been having too good a time - wife walked out while I was at work leaving our 2 sons with me , thankfully.
That probably another thread though, thanks for the reassurance ( hopefully).