A Mexican billionaire has been ranked as the richest person in the world, the first time the title has been held by a non-American for 16 years.

Telecoms tycoon Carlos Slim Helu saw off Microsoft boss Bill Gates and investor Warren Buffett to claim the top spot.

Slim Helu controls a string of companies, including Telmex and America Movil, and has a net worth of 53.5 billion US dollars (£35.7 billion).

In the UK, the Duke of Westminster Gerald Cavendish Grosvenor was again the wealthiest man, as he has been for much of the past decade.

Property tycoons David and Simon Reuben were second in the UK, followed by high street billionaire Sir Philip Green.

All three have increased their wealth despite the recession, with the Duke gaining 1 billion US dollars (£668 million) to amass a total net worth of 12 billion US dollars (£8 billion).

The Reubens are worth £5 billion, while Green has a fortune of £4.5 billion.

Gates was knocked off the top spot for only the second time since 1995 despite gaining 13 billion US dollars (£8.7 billion) in the past year. In 2008 Buffett was ranked as number one.

Forbes published its 24th list of the world's richest people, which saw the number of billionaires rise from 793 last year to 1,011 now. It has yet to reach the 2008 total of 1,125.

The ranking of more than 900 of the world's richest people includes 29 Britons and a total of 97 new billionaires from across the globe.