Countries from Britain to Afghanistan pledged on Thursday to set up public registers of company ownership in a collective effort to make it harder to launder the proceeds of corruption around the globe.

U.K. Prime Minister David Cameron announced the measure at the start of a global anti-corruption summit he is hosting in London, but critics said the proposed registers may not make a meaningful impact unless tax havens ended secrecy as well.

The buildup to the event was marred by Cameron being caught on camera describing Nigeria and Afghanistan, which are both taking part, as "fantastically corrupt," but he later said that the leaders of both countries were tackling the problem.