Tim Worstall explains why it would make no sense whatsoever to impose taxes on the winnings from betting:
The point about betting of all types, including this spread betting, is that the winnings of some people are, and must be, entirely offset by the losses of others. Yes, certainly, there are companies in the middle who organise things and they are taxed on their earnings and profits in the usual manner. But the winnings of some punters come from the losses of others.
It’s also a pretty standard part of the UK taxation system that if there is going to be tax charged on the income or profits of something then there will also be an equal allowance against losses on doing that same thing. For example, Gordon Brown changed the law on a company selling a subsidiary: no longer would corporation tax be changed on any profits from doing so. But so also a company could not claim a tax credit for a loss from doing so.
So, if we introduced a tax on betting winnings we would also need to have a system of credits or allowances for betting losses. And here’s the problem with that idea: betting is a less than zero sum game. The winnings of any person or group of people are obviously the losses of all other people betting. So tax charged would be equal to tax credits gained. But it’s worse than that as the bookies are also getting their slice in the middle. Meaning that total winnings are less than total losses. So our credits and allowances for losses would be higher than any revenue gained from the winners.
