Britain's super-rich have seen their fortunes collapse by half in the economic downturn, with more than £200 billion of their money just melting away.

Research for the 2009 Sunday Times Rich List, to be published in the spring, suggests that the fortunes of the 1,000 wealthiest people in the UK have fallen more than 50% from £412.8 billion in the list for 2008 to about £200 billion.

The value of some assets, including hedge funds and property firms, has been shattered by as much as 90%.

The destruction of the wealth of Britain’s richest is so great and sudden that it has been likened to the bursting of the South Sea bubble in 1720 or the depression of the early 1930s.

Those who have seen their fortunes decline most spectacularly include Lakshmi Mittal, the steel magnate who has topped the Rich List for the past four years and who, in this year’s list, had family wealth of £27.7 billion. He is now worth about £11 billion.

The mining tycoon Anil Agarwal has seen almost £1.5 billion knocked off the value of his stake in Vedanta Resources – he now has less than £1 billion.

Other significant fallers include Sir Tom Hunter, the sportswear tycoon, and Sir Stelios HajiIoannou, founder of the easyJet airline.

The fortunes of some entrepreneurs who made their money in hedge funds have largely evaporated. Philip Richards, a former army captain and founder of RAB Capital, has seen the value of his stake in the company fall from £73m to about £14m.

William Rubinstein, professor of modern history at the University of Wales, Aberystwyth, and co-author of The Richest of the Rich, which traced the wealthiest people in Britain since the Norman Conquest, said: “These figures suggest that only the 1930s and the South Sea bubble are comparable in scale to what is happening now.” In the early 18th century, swathes of society from nobles to Oxford dons, clergymen and even King George I, risked their money on shares in the South Sea Company. It had been granted exclusive trading rights in South America and also took on some of Britain’s national debt.

Ramped up by insider dealing, bribery of ministers and outrageous claims about trading prospects, its shares rose tenfold in less than a year to £1,000. When the bubble burst the shares collapsed to £170 in less than three months.

The king lost £56,000, equivalent to £800m in today’s money. But even that sum was dwarfed by the losses of the Duke of Chandos, who was out of pocket by anything between £300,000 and £800,000, more than half his fortune.

The stock market crash and depression that hit Britain from 1928 to 1933 saw comparable destruction of wealth, according to Rubinstein. Fortunes based on industry in the north, Midlands and Wales were hardest hit, while City wealth and landed estates were less affected.

In today’s downturn, the near-collapse of the global financial system, huge falls on stock markets – 34% in London since the start of the year – and plummeting values across assets from shares to property and art have hit almost every part of the Rich List.

One of the 75 billionaires on the 2008 Rich List, who did not want to be named, said: “The ones left standing are the people with lots of money and liquidity.”

One in six of those on the 2008 Rich List are in finance and their estimated worth is down by more than 70%. The hardest-hit include 50 multi-millionaire housebuilders who have seen values sink by up to 90%. Almost a quarter of those on the list owe their presence to property. Commercial property is down almost 30% this year.

Hunter has lost his billionaire status, but not as he intended – by giving his fortune away to charitable causes in his lifetime. Instead, he has lost £35m on Crest Nicholson, the housebuilder, and another £35m on McCarthy & Stone, the retirement home specialists. He was worth £1.05 billion in the 2008 list but if all his assets were liquidated tomorrow he believes he would be worth about £750m.

“I am tightening my belt like everybody else,” he said. “Yes, I still have the private jet but we have sold our house in the south of France. Everybody is looking at their costs and everybody I speak to is more pessimistic about 2009. I haven’t really met anyone who is immune to all this,” he said.

Mittal is the biggest faller of all. At the start of this year – the valuation date for the 2008 Rich List – his family stake in ArcelorMittal, the world’s biggest steel company, was worth £25 billion but then soared to more than £33 billion in the summer. That stake is now down to £9.5 billion. His spokesman said: “He doesn’t comment on his personal affairs. He is hardly immune to things but he is not affected by them the way most people might be.”

Charles Dunstone’s stake in Carphone Warehouse is now worth £276m, down on his 2008 Rich List valuation of £904m. Sir Richard Branson will also take a dive in the 2009 Rich List. Values are collapsing in every sector in which his Virgin group operates – from planes and trains to media and financial services. Virgin Media shares are down to a quarter of their level a year ago.

HajiIoannou, the largest shareholder of easyJet, has seen his fortune slump from £812m in the 2008 list to about £500m now.

The entrepreneur, who lives mostly in Monaco, said he had paid off his loans earlier this year and the recession would have only a limited effect on his lifestyle, despite his “bearish” view of the airline industry’s short-term future.

“I will still travel by black cab or public transport in London and I’ll still get the easyBus to Gatwick to fly easyJet to Athens or Nice,” he said.

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