HGVs haven't been allowed to use the outside lane on motorways for years. But they're not the problem in any case. As a matter of fact, they're some of the most highly trained, committed drivers on the roads. The problem is people who really don't need to be on there in the first place. A better idea would be to restrict motorway travel during the week to commercial vehicles and public transport only.
Even better would be to stop building/widening more roads. People get more roads to drive on, they go and get more cars to drive on them, thus the roads become more congested, so we build still more roads, and on and on it goes. If we didn't build roads, people would get p'd off with never being able to get anywhere and would find alternative means of getting around - leaving the roads free for those who really do need to use them, viz, our truckers.