Saudi prince Alwaleed bin Talal sues Forbes after it claimed he's 'only' worth $20billion (he says he's worth at least $30billion)

A Saudi prince has claimed that a list charting the world's richest richest people has understated his massive wealth.

Prince Alwaleed bin Talal has severed ties with Forbes magazine after its annual list estimated his net worth at $20billion (£13billion).

The figure saw the investor ranked at number 26 on the rich list joint with American Carl Icahn and Canadian media mogul David Thomson.

But the prince's office has claimed that his net worth is more like $29.6billion (£19.5billion), a figure that would have put him in Forbes' top ten just behind L'Oreal heiress Liliane Bettencourt.

He accused the magazine of a 'flawed' valuation method that 'seemed designed to disadvantage Middle Easte investors and institutions'.

Although he has said he will no longer provide Forbes with details of his finances, he said that he will still work with rival list the Bloomberg Billionaires Index which was set up as a rival to the magazine's list in 2012.

The Bloomberg list estimates the net worth of the prince, who owns the investment firm Kingdom Holding Company, at $28billion which puts him at number 16.

Alwaleed is reported to have written to Forbes editor-in-chief Steve Forbes and is said to have instructed his lawyers over the matter.

The prince is said to have asked to be removed from the list.

He alleges that Forbes refused to accept valuations of his company's stocks on Tadawul, the Saudi Arabian stock market, but says that the index takes into account valuations on other emerging markets.

His office also alleged that there were inconsistencies in Forbes's reporting including allegations that stock manipulation is 'the national sport' in Saudi Arabia.

Splashing out: The prince, centre, is pictured buying the first Airbus A380 double decker luxury jet in November 2007

The magazine this afteoon published an article on its website from next months edition claiming that the prince overestimates his wealth.

This year's Forbes list saw Mexican billionaire Carlos Slim named the world's richest man for a fourth year in a row, with an estimated wealth of $73billion (£48billion).

Microsoft's Bill Gates held on to his spot at second place while Amancio Ortega, owner of clothing brand Zara leapfrogged Warren Buffett into third place.

The top Briton on the list was the Duke of Westminster with a fortune of $11.4billion (£7.6billion).

Wealthy: Mexican Carlos Slim, left, held onto the top spot in Forbes's list for the fourth year running, while Microsoft's Bill Gates, right, was second on the list

Prince Alwaleed bin Talal describes himself as the 'world's foremost value investor', according to Forbes.

The 57-year-old's company has a stake in Four Seasons Hotels and Resorts, Movenpick Hotels and Resorts, Fairmont Raffles Holding, the Hotel George V in Paris and the Savoy Hotel in London.

He is reported to have bought a three per cent stake in Twitter in 2012.

He was also the first individual to buy an Airbus A380 double decker plane in 2007 and it was due to be delivered this spring.

But the Airbus has now been sold according to his office.