In the UK why do some drivers ignore the 50mph speeding sign in certain places on the motorway?

Why do certain drivers prefer driving faster even if there are cameras? I tend to stick to the 50 mark or at least try not to go faster than 55. I move lanes because certain drivers don’t care about the speed limit, tailgating the heck out of me!

Don’t they get flashed?

Thanks
4 answers 4