British Prime Minister David Cameron announced plans Thursday to stop the flow of dirty money through the London property market, as he prepared to welcome world leaders and NGOs to an anti-corruption summit.
The foreign firms that own more than 100,000 titles in Britain, many of them anonymous offshore companies, will have to reveal their true owners, as will any foreign firms buying new property or bidding for government contracts.
The measures, intended to combat money laundering, were announced as Cameron seeks to build on public anger over the leaked Panama Papers to secure a new global commitment to tackle corruption at the summit.
The presidents of Nigeria, Afghanistan, Colombia, Ghana, Norway and Sri Lanka, US Secretary of State John Kerry and the heads of the World Bank and IMF are among those attending.
Cameron's efforts were hampered by a gaffe in which he was caught on camera saying that the leaders of some "fantastically corrupt" countries were attending the summit, naming Nigeria and Afghanistan.
Nigerian President Muhammadu Buhari, who has embarked on a widespread anti-corruption campaign since taking office last year, responded with a pointed request that Britain return assets stolen by corrupt officials who fled to London.
Cameron later paid tribute to the efforts of both Buhari and Afghanistan's Ashraf Ghani in tackling corruption, and in a statement acknowledged: "The evil of corruption reaches into every corner of the world.
"A global problem needs a truly global solution. It needs an unprecedented, courageous commitment from world leaders to stand united, to speak into the silence, and to demand change."
There were reports however that the final declaration was being watered down following opposition from some countries.
It was also unclear exactly who would be signing up, with officials only confirming a handful of the 50 nations said to be attending the summit.
- 'Tip of the iceberg' -
The move to shine a light on the property market in Britain, particularly in London, where 44,000 titles are owned by foreign firms, had been well trailed and was welcomed by transparency campaigners.
More than £180 million ($260 million, 228 million euros) of property in Britain was investigated as suspected proceeds of corruption between 2004 and 2014, according to Transparency International, which says this figure is just the "tip of the iceberg".
Britain also announced it would set up a new international centre, with help from the US, Canada, Australia, New Zealand and Switzerland, to help coordinate global anti-corruption efforts.
It also hailed France, the Netherlands, Nigeria, and Afghanistan for taking the same action as Britain in creating a public register of who ultimately owns all companies incorporated in those countries.
This register will not be extended to Britain's overseas territories, however, despite demands by campaigners to introduce a move they said would open up key players in global financial secrecy.
More than half of the 214,000 companies represented by the Panamanian law firm at the centre of the leaks, Mossack Fonseca, were incorporated in the British Virgin Islands.
Instead, some of the overseas territories are among 40 jurisdictions automatically sharing company ownership details with law enforcement agencies under a new deal, officials said.
Territories such as the Cayman Islands, which will be represented at the summit although the BVI and Panama will not be, say a public register is unnecessary.
Jose Ugaz, chairman of Transparency International, a leading advocacy group, welcomed the move on public registries.
"Bit by bit they are making it harder to hide the proceeds of corruption. But we need more progress on public disclosure of company information," he said.
Robert Palmer, of campaigners Global Witness, added that the government announcements represented "good progress", "but the biggest piece of the puzzle is still missing -- the tax havens must open up."
In an interview with the Guardian newspaper, French Finance Minister Michel Sapin urged Britain to "go right to the end" to enforce the same levels of transparency in the tax havens as elsewhere.