An international deal to crack down on secretive tax havens is in jeopardy after the British Crown Territory of Bermuda refused to sign up to new transparency rules. Tax avoidance had been placed top of the agenda for the G8 summit of world leaders meeting next week in Northern Ireland, and David Cameron has called Britain’s 10 overseas territories and crown dependencies to talks on the topic in London this Saturday. The Prime Minister had hoped to persuade them to agree to a new convention drafted by the Organisation for Economic Co-operation and Development (OECD) to give momentum to his drive for transparency. But the plan is now in doubt.