When George Soros speaks, the global financial community listens. Yesterday, when the 67-year-old financier and philanthropist gave warning that the world was facing its most serious financial crisis since the Second World War, the statement struck home in both timing and tone, on one of the worst days for the world's stock markets in years.

Mr Soros is most famous for almost single-handedly driving the pound out of the European exchange rate mechanism on Black Wednesday in 1992, earning him the title “the man who broke the Bank of England”. He sold short more than $10billion worth of sterling, profiting from the Bank's reluctance either to raise its interest rates to levels comparable with other European Exchange Rate Mechanism countries or to float its currency.

Mr Soros is not one to shy away from controversy. In 1997, during the Asian financial crisis, the then Malaysian Prime Minister, Mahathir bin Mohamad, accused him of bringing down the Malaysian currency, the ringgit, through his trading activities. In Thailand he was branded an “economic war criminal” who “sucks the blood from the people”.

In 1988 Mr Soros had been asked to join a takeover attempt on the French bank Société Générale. He did not participate in the bid but did later buy a number of shares in the company.

In 2002 a French court ruled that it was insider trading and fined him $2 million. Mr Soros denied any wrongdoing and said news of the takeover was public knowledge. His insider trading conviction was upheld by the highest court in France in 2006 and he appealed to the European Court of Human Rights, claiming that the 14-year delay in bringing the case to trial precluded a fair hearing.

Mr Soros is the founder of Soros Fund Management. In 1970 he also co-founded the Quantum Fund, one of the first hedge funds. This vehicle has created the bulk of his immense wealth.

Mr Soros was born in Budapest in 1930. His father, the Esperanto writer Tivadar Soros, was taken prisoner during the First World War but eventually fled from captivity in Russia to return to his family.

Mr Soros was a teenager when the Nazis invaded Hungary in the Second World War but he avoided the fate of many Jews. In 1946, as the Soviet Union was taking control of Hungary, he defected. Emigrating to England, he supported himself by working as a railway porter and a waiter while studying at the London School of Economics, from which he graduated in 1952.

He then obtained an entry-level position with an investment bank and in 1956 moved to the United States.

It was there that he became acquainted with the work of the philosopher Karl Popper. Adapting Popper's ideas to develop his own “theory of reflexivity”, which attempts to explain the relationship between thought and reality, Mr Soros used the theory to predict, among other things, the emergence of financial bubbles.

Mr Soros is also a renowned philanthropist. In 1979 he began providing funds to help black students to attend the University of Cape Town in apartheid-era South Africa.

He later set up a foundation in Hungary to support culture and education and the country's transition to democracy.

Mr Soros has been married twice and has four sons and one daughter.