I'm starting with the assumption that gold is sometimes useful for diversifying risk, responding to economic instability, or generally commodity trading. That stated, there are obviously different ways of investing in gold, with different costs and risks: coins, bars, stocks.
In the UK gold coins and bars are VAT free, but gold sovereign (also Britannia?) coins are, uniquely, capital gains tax free. I wonder then, if we have a view to invest in gold; are gold sovereigns a worthwhile consideration for a British citizen? And is the fact they are more expensive to buy/transport/store/insure than something like shares, ever offset by their exemption from capital gains tax?
EDIT: I'm not asking "is gold a good investment?", I am asking specifically regarding the aforestated tax status of aforestated gold coins in the UK, and thus how this compares against other means of investing in gold. I hope that clarifies the question.