DickyNick:
Who really needs to reacquaint themselves with the Highway Code. The car driver who is driving at a perfectly legal 50mph and has moved out to pass a junction to allow traffic to join… or the PROFESSIONAL driver who clearly:
1/ doesn’t understand stopping distances
2/ doesn’t understand that he may kill someone if the car brakes
3/ doesn’t know the correct use of a horn
4/ doesn’t know the correct use of headlight flashing
5/ is so impatient 30 seconds matter
Out of those 2 which one REALLY needs some re training and to read up on the rules?
I stand by my original comment. The car driver shouldn’t be on the road. No excuse for poor standard of driving, as that is why driving tests exists. Unless the car driver was old enough to have a licence without passing a test? 
The car driver claims to be doing 50mph but how was that indicated? Most car speedos are out by 10% or sometimes more. Perhaps much more if the car driver was cheap/clueless and went with a slightly cheaper size of tyre…
So lets assume the car was in proper condition for the road. 10% error on the speedo puts the car driver at 45mph.
Truck driver can do an accurate 56mph, perhaps slightly more if the road was a on a downhill section
So Artic driver is trundling along in Lane 1, gaining on a car claiming to be doing 50 but more likely to be doing 45,perhaps less. The car driver then moved into lane 2 where Artic driver had moved to, trying to pass the car. The car is not overtaking anyone but has simply moved out to impede the progress of the artic driver. This is in effect “Brake Checking” with such a difference in speed, a very dangerous and illegal activity.
Artic driver uses the horn and flashes lights to make sure the car driver is aware the artic driver is there, as is legal and even recommended in the highway code.
Sounds to me like the car driver has a potential charge of dangerous driving to answer for, should the artic driver have a dashcam recording and sent to the police.
If the artic driver was so close, being the claimed inches off the car driver’s back bumper, the car driver would not have been able to see the artic having his high beams on - Which puts into question how close the artic driver really was from the car.
The car driver was wrong - There is no excuse for dangerous driving, not even nerves or lack of experience. The car driver was lucky this time their activities didn’t result in damage, injury or a fatality. Next time they might not be so lucky.