Cam car is as much, if not more at fault as the guy undertaking. KU06 NRN was not driving at excessive speed and only undertook as the cam car was hogging lane 2, which is also an offense.
Rule 264
You should always drive in the left-hand lane when the road ahead is clear. If you are overtaking a number of slower-moving vehicles, you should return to the left-hand lane as soon as you are safely past.
Reckless driving nearly caused accidents in the road