hypothecation

This is called "hypothecation" and has been advocated in the past to reassure voters their money is key to public services.

If the Treasury was obliged to top up funding from the central pot, the benefits of hypothecation would be lost.

Known as hypothecation, this is very much out of fashion at the Treasury which prefers everything to go into a central pot, but helps sell tax hikes to the public.

"Hypothecation, allocating taxes raised to specific purposes, can make absolutely clear where tax money is being spent," he said.

There’s other change that need to be made to it, certainly, most especially getting rid of the ridiculous system of hypothecation, but taxing gas is, in so far as there are ever good taxes, a good tax.