A rearguard action to fend off the “action against tax and regulatory havens” threatened by Gordon Brown and other world leaders is being launched by some of Britain’s Crown Dependencies and Overseas Territories.

They are among 35 small states and territories braced for possible sanctions after the US administration last week endorsed anti-tax haven legislation and political leaders in France, Germany and the UK stepped up their anti-haven rhetoric ahead of next month’s G20 meeting.