It must be one of the main reasons for the huge loss of business of UK flying schools to the states.
Given a light aircraft probably uses £30/hr of Avgas - if the tax was slashed and this came down to £10/hr, that would give the UK flying schools a huge boost if they could pass that on to their customers. It would cut £800 off the cost of a PPL!
I run on Mogas and own two very large jerry-cans (and an aircraft that burns 2 gallons an hour) but this is hardly an option for everybody. Also MOGAS is getting worse and worse.
G