One of my absolute bane’s this one, along with not indicating. Undertaking, as far as I am aware, is not illegal but can be considered careless driving in some circumstances. If I am on a motorway driving at 70mph or less on the inside lane and come across a lane hogger in the outside or middle lane, I would continue at the same speed and in the same lane. Highway Code 268 “Rule 268 Do not overtake on the left or move to a lane on your left to overtake. In congested conditions, where adjacent lanes of traffic are moving at similar speeds, traffic in left-hand lanes may sometimes be moving faster than traffic to the right. In these conditions you may keep up with the traffic in your lane even if this means passing traffic in the lane to your right. Do not weave in and out of lanes to overtake.” I would argue in any court if I was in the left hand lane and pass a lane hogger that the above applies. ???
I was going to ask a question regarding the above, but you have answered it
Unfortunately I have suffered a brain injury and occasionally I get confused and often say the wrong thing.