In common with other posters on this thread, I think the root of the problem lies in the woeful lack of ongoing driver education / training / testing in the UK.
The problem starts with the novice driver who has probably amassed zero experience of driving on multi-lane divided highways prior to passing their driving test. They certainly have no experience of motorway driving before passing their test. They're then let loose, generally with no guidance, on the motorway network with nothing more than hope and good fortune to stop them being part of a very unpleasant incident. Is it any wonder that they don't get it right?
The fact is that there are a large number of drivers who think that lane 1 on a motorway is for slow traffic (especially lorries), lane two for medium speed traffic and lane 3 for fast traffic. I have had the misfortune of being a passenger with more than one driver who was quite happy to cruise along in lane 2 for mile after mile at 60-65mph while lane 1 was perfectly usable. When I questioned one of them what their rationale was they told me, "I don't like using the slow lane (sic) because I feel unsafe pulling into the middle lane to overtake slower traffic". What???? So why, if you lack the skills and judgment to use it safely, are you on a motorway then????
In my view we need to have a concerted publicity campaign (think: Clunk-Click) to encourage people to use motorway and dual carriageway lanes more effectively, a serious look at how new drivers can be encouraged to be effectively trained to use motorways (perhaps a post-driving test certificate or diploma that entitles them to an insurance discount?) and also some non camera-based enforcement for those who still don't get it right. The payback would be less congestion, less frustration and and less motorway shunts.