The British prime minister has chosen a keynote speech in America to step up his attack on offshore tax havens.

Gordon Brown has been speaking to both houses of Congress on Capitol Hill about how the United Kingdom and United States can work together, and push for economic changes.

He spoke about the dangers of protectionism and how the global financial system should be regulated.

There were no specific references to the type of jurisdictions he had in mind, but Mr Brown told his American audience:

"How much safer would everybody's savings be if the whole world finally came together to outlaw shadow banking systems, and outlaw offshore tax havens."