I think the problem here is that far too many people refer to motorway lanes as "fast lane", "slow lane". I've even heard & seen (on YT comments) daft remarks like slow & fast lanes, even giving them speed limits of 50, 60 and 70 respectively.
As this has never ever been taught, I can only assume that people have imagined these new rules into existence because of lane 1 being used by lorries @ 56 (slow)?
Undertaking is illegal, however, if you've just driven miles (for example) in an almost empty lane then come across some muppet pootling along at 60 in lane 2 & decide to drive on by in lane 1, this is not undertaking.For some reason I feel as though these are the same people who take offense at someone travelling in lane 1 undertaking at 70...entirely unaware they're causing it. Yes we all know it's illegal, but if you're sitting on the cruise in empty lane 1, you've been up for 14 hours and you still have 2 hours left on your trip going all the way out to lane 3 and back again because of one idiot suddenly seems like far too much effort..