There is nothing illegal about moving money offshore. To begin with, during the 1970s it was a way of moving cash around at a time of widespread currency controls across Europe.
Buying and selling dollars, for instance, was much easier for banks if the trades were done offshore. If you lived in a country where a corrupt or predatory government might seize your assets, then moving your wealth offshore to protect it also made sense.
But the offshore industry has evolved substantially since then. And the secrecy surrounding it has become increasingly unpalatable for world leaders, who have been calling for more transparency. David Cameron and Barack Obama chief among them.
The US president said on Tuesday that “global tax avoidance generally is a huge problem”, adding: “The problem is that a lot of this stuff is legal, not illegal.” Cameron has also criticised complex offshore structures, saying they are