Financial bookmakers in London had calls pouring in yesterday following a report that a punter landed a windfall of £3 million after staking just £5 on the performance of the world's stock markets. The Guardian newspaper said that the gambler from the City was a client of City Index, London's largest financial bookmaker, which is owned by brokerage Inter-Capital.

The gambler, whose name has been withheld, built up his winnings by placing bets on moves in currency and share prices, starting with a small spread bet on the French franc falling against sterling.

In the last year, he correctly predicted every financial move from the rapid rise of sterling to Wall Street's bull run.