Forbes richlist: Carlos Slim world's richest billionaire

Mexican tycoon Carlos Slim tops the Forbes magazine's annual list of the world's richest billionaires for the third time.

The magazine estimates that Mr Slim, whose business interests range from telecommunications to construction, is worth $69bn (£44bn).

He was closely followed by Microsoft founder Bill Gates worth $61bn and US investor Warren Buffet on $44bn.

Tom Esslemont reports.