Yes, agreed, we're very bullish about offshore and tax avoidance - it reduces the amount that can be shaken out of the rest of us. Similarly, agreed, there are those who don't agree with us. But then, far over on the other side, are people who believe entirely ridiculous things:
The argument that “if you tax it, we’ll leave” is fatuous when the money has already gone offshore. From the perspective of the British economy that money might as well have been taxed at a rate of 100% – it’s not paying wages or buying machinery, it’s just sat idly in Bermuda and other havens, with exactly the same effect on growth as if the government had taxed it into oblivion, and the profits that produced it not existed in the first place.
The ridiculous thing here is to believe that the offshore money just piles up in cash. No, really, Scrooge McDuck surfing down his pile is a cartoon. A joke for kids. That money is invested. Even if it's just piled up in bank accounts the banks then lend it out again (or, for purists, use the deposits to fund loans they've already made). There really isn't any pot of cash or gold sitting somewhere doing nothing.
But even better than this think about what would be true if here were that unused stash. That money is not, therefore, in the British economy. Thus there's no tax avoidance, is there? Because we Brits, the British government, do only get to tax the British economy. The money's not here, it's not invested here, it's not doing anything here, then there are no taxes being dodged, are there?
The real complaint is that it is invested here, is paying wages, buying machinery, but not in the process paying the vig to Westminster for the privilege of doing so. That's the only way there can be that avoidance (or even evasion) isn't it? Something that's entirely inconsistent with the assertion that it's not here currently, isn't it?
Then of course we can go off into economics and point out the basics of the taxation of capital. The more you do so then the less foreign capital you're going to attract to be taxed, the more domestic will leave to avoid it. But that would be complicated and subtle, something obviously beyond the ken of the Guardian here given the ridiculous things they seem to believe.