Modest origins of Britain's £15bn man

The sheer scale of Mr Mittal's wealth was not apparent to the outside world until last year, when he announced a complex deal in which all his steel interests combined into a publicly listed company.

Mr Mittal's private LNM Holdings was taken over by his listed entity, Ispat International. He paid himself a £1bn dividend in the process. The merged company then took over ISG, the leading North American player, for $4.5bn (£2.5bn), to form Mittal Steel Company, the clear global leader.

Mittal Steel is listed in Amsterdam and New York, with a stock market value of $20bn. The free float is just 12 per cent; Mr Mittal and family own the rest.

At the age of 21, Mr Mittal started working in the small family steel business, Ispat, which at the time operated in Indonesia. The company grew and took advantage of the recession of the late 1980s and early 1990s by making a string of acquisitions, entering markets such as Mexico, Trinidad and Canada. From that base, the acquisitions have kept on flowing.

Mr Mittal recently announced the company's first investment in his native India, now a key growth market, where he will build a $9bn plant that will produce 12 million tonnes a year of steel.