A lucky gambler placed a £500,000 bet on a horse - and won.

''With measly interest rates, and a volatile stock market, the punter was obviously banking on Big Buck's.''

The wager - the biggest single bet bookmaker William Hill has taken in its 78-year history - was placed on Big Bucks to continue his record-breaking winning streak of 16 consecutive victories.

The horse romped home to victory on the first day of the Grand National Festival meet at Aintree, Merseyside, winning the unnamed punter 100,000 after he placed his half a million pounds on at odds of 1/5.

William Hill spokeswoman Kate Miller said: ''This ranks as one of the biggest bets ever taken on racing.

''With measly interest rates, and a volatile stock market, the punter was obviously banking on Big Buck's.''