It’s great that the United Kingdom gathered leaders to fight corruption, but Cameron should also get his own house in order. London is a world haven for dirty and ill-gotten riches, including from Ukraine and Russia.

In fact, most of the wealth leaving poorer countries ends up in tax shelters or real estate in wealthier Western nations. There is no global super agency to crack down on tax avoidance and fraud. But Great Britain and the United States can do more by investigating sources of money, saying no to shady money, sharing bank information with other governments and pooling investigative resources to stop this grand-scale theft or legalized corruption that robs billions of people in the world of better lives.