Britain promised Thursday to take the lead in the global fight against corruption by launching an international anti-corruption centre, sharing information on company ownership and forcing foreign property buyers to reveal the original source of their funds.
"I believe that corruption is the cancer at the heart of so many problems we face in the world," Prime Minister David Cameron said at the opening of an anti-graft summit in London, highlighting problems including poverty, terrorism and money laundering.
"First of all, what we're doing is to expose corruption, where the absolute key is transparency," he told delegates from 40 nations, 11 heads of state.
US Secretary of State John Kerry said Thursday's summit could be "the beginning of something different."
"I've been shocked by the degree to which I find corruption pandemic in the world today," Kerry said, saying it "destroys nation states."
"We have to say no safe harbour anywhere, and get the global community to come together," he said.
About a dozen protesters from anti-poverty group ONE gathered close to the summit, shouting slogans and holding a large placard reading "It's a scandal, 170 billion dollars stolen. Stop tax havens."
In an embarrassment for Cameron ahead of the summit, broadcaster ITV showed video footage of him saying Nigeria and Afghanistan - two of Thursday's participants - were "possibly the two most corrupt countries in the world."
Speaking in parliament on Wednesday, Cameron appeared keen to mend fences, saying Nigeria and Afghanistan were "battling hard" against corruption and had taken "remarkable steps forward."
Reacting to his comments, Cobus de Swardt, head of anti-corruption group Transparency International said the two nations were highly corrupt but their leaders had "sent strong signals that they want things to change."
"We should not forget that, by providing a safe haven for corrupt assets, the UK and its Overseas Territories and Crown Dependencies are a big part of the world’s corruption problem,” de Swardt said.
Cameron said the summit participants will issue a joint declaration stating a "shared ambition to tackle corruption," and set out a common approach to tackling corruption.
Ahead of the summit, Irish musicians Bono and Bob Geldof were among 20 well-known people who signed an open letter urging the leaders to take eight steps to "help create a new international norm – a Fair Play Standard."
"We must act together with courage, ambition and urgency to put an end to this scourge [of corruption] and make our world a fairer place,"they said in a letter circulated by ONE.