Gordon Brown and New Labour have bankrupted the UK so he is now desperately trying to grab cash from wherever he can. According to this report in the Grauniad world leaders are drawing up plans to shaft tax havens which 'cost' the top economies £100bn each year in tax avoidance.
I'm not sure how Switzerland, the Cayman Islands and others will respond to this but I guess they won't just declare "oh go on then" and roll over. Who knows, perhaps like spreading democracy they will get the crap bombed out of them in the interests of fiscal equality.
I prefer to see independent nation states setting their own rules and levels of taxation. Perhaps if so many countries, such as the UK, didn't have such high taxes, and squander so much of its tax revenue, then people would be happy to pay a little more rather than looking for perfectly legal loopholes.