If the tax the user idea means more or less scrapping road tax and sticking it on the fuel - then great.

If they intend on retaining the road tax as well as charging for usage, then boo.

Have a current road tax bill p/a of roughly 3.5k, and I pay 1k per year for my train ticket - which I use every day, so would be slightly infuriating to be even further buggered on taxes. Given theres little or no further capacity on public transport - I'm not quite sure what they expect people to abandon cars in favour of.