Idiotic drivers, Glasgow brake checking

Driving back from Liverpool (Beatles country) on Sunday I encountered this in Glasgow. ("People Make Glasgow" is the city slogan, maybe get rid of these two)
I had just overtaken a car and was about to pull over when I just caught in the mirror 2 cars behind me acting strange, one swerved into the space and started to UNDERTAKE me.
As the BMW overtook me in the correct lane he initially tried to swerve across 2 lanes, but the white car stopped this.
Then came a series of swerving and brake checking each other.
I slowed down to avoid this as I didn't want me or my passengers to become victims of there stupid, reckless and down right dangerous behavior.
I was really relieved, when both of them pulled off at the junction.
This could have been really serious if other drivers hadn't realised what these pair of idiots were doing.
Saying that whilst slowing down to avoid this pair of prats, I got undertaken again.
Some people seem to live in the fantasy of the fast and furious, maybe they thought they were Vin Diesel or Paul Walker. Well news flash - real life is not the movies, when people die in real life they die and there was a good chance you were likely to kill someone with your ridiculous driving.
Idiots, morons or imbeciles you decide.