Britain is set to enforce greater transparency in tax havens after a minister for the U.K. government announced Tuesday it would not oppose a legal amendment proposed by a cross-party alliance of lawmakers.

Some overseas British territories that are notorious for being tax havens for the world’s wealthiest, such as the Cayman Islands and the British Virgin Islands, will now be required to reveal beneficial owners of assets held in a register available to the public.

A total of 40 lawmakers, including 19 from the ruling Conservative party and Ed Miliband, the former leader of the Labour opposition party, had forced the hand of Prime Minister Theresa May to debate an amendment on financial secrecy and offshore money laundering. That debate was set to take place Tuesday before the minister’s announcement.

The U.K. Foreign Office said Monday it had evidence that a century-old loophole has been exploited by money laundering schemes to move up to $80 billion out of Russia.

Laundering schemes use Scottish Limited Partnerships (SLPs) and Limited Partnerships (LPs), both two types of businesses often owned by legitimate firms, as a way to pass dirty money through the U.K.

It also said that five men were responsible for over half of 8,800 “limited partnership” businesses registered between January 2016 and May 2017, with 17,000 companies registered at just 10 addresses.

Global campaign group ActionAid said the government’s u-turn was a “breakthrough” for those calling for greater global financial transparency.

“These measures will help flush out the corruption and tax evasion that keeps the most vulnerable people in the world — including women and girls — locked in poverty,” said Jon Date, senior advocacy manager at ActionAid UK.

A report by an international corruption watchdog last month criticized G-20 countries as being “weak” and moving “too slowly” in improving transparency over financial secrecy, two years after the Panama Papers revealed how wealthy individuals hide their money.

The U.K. remains the only G-20 country to have a central register detailing beneficial owners available to the public. A beneficial owner ultimately has significant control of, or owns, a corporate entity.

The Panama Papers saw the unprecedented leak of 11.5 million documents from offshore law firm Mossak Fonseca in April 2016. The leak raised questions over tax avoidance from prominent individuals, such as the late father of former U.K. Prime Minister David Cameron, to secret offshore deals worth $2 billion with links to Vladimir Putin.