As the UK contemplates an approaching budget, we only have to go outside and look at the potholes in the road, or the queues at our local hospital, to realise that there are many areas where the national finances are struggling.

It's well known that, though it's politically easy to impose an extra tax burden only on the wealthy, this doesn't actually raise much money. But what would? The wonderful Hannah Ritchie, of course, has run the numbers.