"When we went out there, we were shocked to see the extensive use of these machines in orange groves and vineyards, " said Graham.

BBC: Graham Hewitt and his wind machine

So a relatively high-tax country such as France might see a drop in foreign investment if nearby tax havens went out of business, because foreign companies would no longer be able to use them to minimise French tax bills.

ECONOMIST: The less obvious uses of tax havens