Yeah but sometimes its the other way around, your'll get some n0b sat in the fast lane in there big car not overtaking anything, but because there car cost £40,000 and they are doing 70 its ok. God they do my head in. 
Exactly... I do 300 miles commute a day and can't stand it when some t055er thinks their dad built the motorway and decideds to overtake on the outside lane at 60mph... worst culrpits are vans.
Not all of them, especially if it is a MB Sprinter, cause they go like fcuk.
What we really need to do is BAN, permanently, all vehicles with more than 5 seats, all vehicles over 1.5m tall (that will stop fcuking "people" carriers, which never usually have more than one person in them!), all car-derived vans, and any other "undesireables" from lane three of the m-ways.
Furthermore, all commercial vehicles, along with anything towing - should be restricted to lane one only, between the hours of 06:00 to 22:00, and completely banned on Sundays on m-ways. This works in Germany, and with the exception of the Sunday ban, also works in France.
Oh, and scrap the m-way speed limit, but with some notable exceptions near certain danger hot spots.