'Tax havens' agree to clampdown on tax avoidance
15 June 2013 Last updated at 22:53 BST
The prime minister has hailed an agreement by the UK's Overseas Territories and Crown dependencies to sign up to a tax evasion clampdown.
David Cameron said it was a "very positive step forward" ahead of the G8 meeting, which starts on Monday.
But sources from the Crown Dependencies told the BBC a proposed register of companies, revealing the true owners, may not work.
They say it does not include trusts and the UK business community may object.
Joe Lynam reports.