By Keith Weir
LONDON (Reuters) - Britain's golden haul at the Olympics has fuelled business at the country's bookmakers who were sceptical about the likely impact of the Games before they began.
Bookmakers have used the London Olympics to develop markets in a broader range of sports beyond staples like football and tennis and to promote betting via mobile devices, a big growth area for the industry.
William Hill, Britain's largest bookmaker, said the Olympics were far less significant than major football tournaments but the outcome had been encouraging.
"Whilst turnover levels are not in the same league as the likes of the Euros or a World Cup, we have been pleased with how popular the Olympics has been," a spokesman said.
"Following Team GB's amazing successes it's likely we will see the strong emergence of athletics and cycling as desirable betting events," he added.
Britain took seven golds in track cycling, and won three track and field events in a dizzying burst in the Olympic Stadium on Saturday evening.
Betting exchange Betfair said volumes of matched bets were double what they had seen at the Beijing Olympics in 2008.
It said 19,000 customers placed a bet on the 100 metres final when Jamaica's Usain Bolt retained his title, with the amount of money traded similar to an average English Premier League match.
Coral, another of Britain's main bookmakers, said its turnover on the Games was expected to beat its initial 50 million pounds ($78.30 million) estimate.
However, Coral said its margins had been dented by payments to punters who had backed British favourites like heptathlete Jessica Ennis and 10,000 metres runner Mo Farah.
"While turnover is a lot higher than originally predicted, it's also proving expensive for the bookies as Team GB's success looks set to continue the patriotic payouts," said Coral PR Director Simon Clare.
(Editing by Ken Ferris, For all the latest Olympic news go to http://www.reuters.com/london-olympics-2012)