Sounds like an excellent idea and one which we have been rabbiting on about for many years on this forum. Why should foreign lorries use our roads for free and cause so much wear and tear without having to pay for it as UK transport companies have to do through their taxes? Would appear to be an unfair advantage. When I started working on the ferries some twentyfive years ago, the ratio of UK to foreign lorries was about half and half. Now a UK registered truck is something of a rarity. There are of course additional reasons for that, including the price of fuel and drivers wages.
When outbound from Dover to Dunkerque, there is an announcement on the public address every trip for drivers to obtain their Vignettes in the drivers lounge. This appears to be a tax they have to pay on continental roads so why not a tax for travelling on UK roads to assist in restoring a level playing field? And why have they waited so long to introduce it?
http://en.wikipedia.org/wiki/Vignette_(road_tax)