[chriswarbo]

This is kind of a perverse incentive though:

- Discourage "bad" thing (driving, drinking, smoking, sugar, ...) by applying heavy taxes

- Occurrence of that thing goes down

- Complain about falling of tax revenue

I'm generally in favour of applying taxes like this, but they need to be based on the actual harm/externalities, and be targetted effectively. Taxing electricity-used-for-vehicles seems easy to game, and only indirectly related to harm. It might be more effective to tax fossil fuels, both for transport and electricity generation, due to their environmental problems; and tax ownership of vehicles to cover expenses (infrastructure, medical care, ...) and discourage excessive use (reducing fatalities, etc.). We have car tax for the latter; perhaps it could be made proportional to use by checking odometers during MOT? (Although it's currently perfectly legal to alter odometers, as long as it's not used to defraud someone when selling the vehicle)

[gambiting]

>>and discourage excessive use (reducing fatalities, etc.). We have car tax for the latter;

If you mean VED I don't think that achieves anything, perhaps only discouraging people from buying cars with particularly high CO2 emissions, but if you can afford a sports car with 200g/km+ emissions, you can probably afford the annual VED on it. Besides, with VED refresh recently it almost doesn't matter, you only discourage people from buying expensive vehicles as they incur extra tax due to their purchase price, not their emissions.

>>perhaps it could be made proportional to use by checking odometers during MOT?

The issue here is that obviously you have to prove that those miles were done in United Kingdom, and obviously it's not illegal to use your car abroad. Taxing fuel has the nice property of the taxes going into the budget of the country where you buy it, so the assumption is that visitors to the UK will buy fuel here and contribute at least a bit to the UK road budget - and the same goes for British drivers going abroad.

[isostatic]

> The issue here is that obviously you have to prove that those miles were done in United Kingdom

Why? The law could just charge based on miles regardless.

However if you did choose to allow people to exempt overseas mileage you could read the odometers at ports (say charge them £10 for the privilege, so it only makes sense if you're doing a lot of mileage)

Clearly Northern Ireland would have to be exempt.

However mileage is very different, the externalities of a smart car driving 50miles from Lancaster to Carlise at 3AM is far different to that of a 13 ton lorry driving from Luton to Oxford Circus at 8AM -- in pollution generated (locally and globally), in damage to the road, congestion

[chriswarbo]

Hmm, I hadn't thought about foreign travel. Food for thought, thanks!