UK could legislate to force tax havens to reveal offshore ownership,

The government could legislate to force the UK’s tax havens to reveal for the first time the true owners of offshore companies, anti-corruption champion Sir Eric Pickles has indicated.

Pickles described the behaviour of some of the former colonies as “simply unacceptable” during a discussion with civil society groups on Thursday, a day after David Cameron said some “frankly, are not moving anywhere near fast enough” to tackle tax evasion and money laundering.

The crown dependencies and overseas territories, which are self-governing but partially subject to UK law, are fiercely resisting pressure from the prime minister to adopt public registers of beneficial ownership, which would name the true controllers behind companies in tax havens. Public registers are widely considered by campaigners to be essential in the fight against international corruption and tax crime.

Asked by the Guardian if the government was considering legislation to force territories to implement the registers, Pickles said there were “more ways to get to this than through the legislative route”, but suggested that it was one option in delivering reform.

“How to get there, through legislation, guidance or naked pressure, the prime minister is pretty determined to get there,” he said.

The possibility of legislation will raise pressure on the Cayman Islands and British Virgin Islands, both of which have publicly refused to adopt the registers but have reportedly received joint letters from the Treasury and Foreign Office ordering them to present an implementation plan by November.

At the G8 summit in 2013 Cameron called for global action in favour of corporate transparency as a means of defeating corruption, tax evasion and aggressive tax avoidance. The UK will begin publishing information on beneficial ownership of companies in England and Wales next year, and is planning to host an international summit on anti-corruption.