Has Gordon Brown cut CGT in his time in power? He implied yesterday that he had.

On one level, of course he's right. The rate used to be 40%, and now it's (going to be) 18%. But it isn't really as simple as that - the old 40% rate carried with it the inflation allowance that reduced the bill according to indexation relief.

Another measure might be whether the tax has raised more money since 1997.

The CGT take in 1997/8 was, according to Treasury figures, £1.5bn. If that take had increased with inflation, it would sit at around £2bn today. But the estimate for 2006/7, from the Treasury, is £3.9bn.

That of course might mean purely that Gordon has been so successful in shepherding the economy that people have been making an awful lot of money and thus paying tax on it.

That may be partly true - the CGT taper relief scheme must have stimulated private equity, some might say a bit too much. But there's probably also an element of reduced avoidance of the tax, or more likely people avoiding income taxes by rolling up income as gains. (some might say that's what the private equity chiefs have done).

So has Gordon reduced the tax? Well, there are winners and losers.

You'd only have to hold a business asset for two years to reduce the rate to less than 18% under taper relief rules. (something you'd never achieve with a non-business asset).

Is the government raising taxes now with the 18% flat rate? The winners and losers have already been discussed ad infinitum, but look at the policy effect. According to the Treasury, the move will raise £2bn [pdf, p8] extra over three years.

Whatever the situation, it seems a bit rich for Gordon to boldly claim he is a tax-cutter: the situation is a good deal more complicated than that.