Chancellor George Osborne has announced plans to stop multinationals hiding their profits from the taxman in shadowy offshore “shell” companies.
He pledged to set up a UK register of beneficial ownership – which could be open to the public – to make it clear who was gaining from such arrangements.
The US has also backed the idea, although it is not yet clear if all G8 nations will agree to the plan.
Mr Osborne said more progress had been made in 24 hours than over “24 years”.
Tax, trade and transparency – dubbed “The Three Ts” – were placed at the top of the UK’s agenda for its presidency of the G8, which includes the UK, US, Germany, France, Italy, Russia, Canada and Japan.