I have NC for this....
In the 1980s HMRC legislated so that there is no difference between how a UK fund is taxed or an offshore fund is taxed. So up intil 2009, if a fund distributed most of its income as dividends then investors were allowed to apply capital gains tax rates when they sold their investment in the fund. A UK fund works in exactly the same way. For UK investors to get CGT treatment HMRC had to examine the fund and give a certification.
In 2009 the legislation changed and offshore funds had to report all of their income, but didn't have to pay it out as dividends (ie you pay the tax even if you haven't received the cash).
Every journalist appears to have missed a couple of basic facts....
HMRC examined this fund every year, which means that in the old days it paid out all of its income so there was no tax advantage.
HMRC publishes a list on its website of all the funds it has examined and certified. Cameron's fund is there on the old list and the new list. It took me 30 seconds to find both lists.
If he had just come out and said, yes I did invest in the fund, HMRC has examined this fund for almost 30 years each year, it would have looked less dodgy. And less exciting.
Oh and looking at what the fund is actually invested in, if the fund had been based in the UK it would have paid LESS tax, not more, even in the days of 33% UK corporation tax rates. 