Shares in the UK bookmaker William Hill have fallen by more than 7% after the company warned that recent horse racing bets had gone against it.

The share price fell despite the company reporting a 32% rise in pre-tax profits before one-off items to �80.1m during the first half of the year.

The World Cup brought better times for William HIll

The results were the first since William Hill floated on the London Stock Exchange in June this year, but the costs of flotation meant that overall it made a pre-tax loss of �12.2m.

Turnover jumped by 47% to �1.59bn, helped in part by the World Cup.

The bookmaker said the World Cup had attracted new customers, especially to its internet betting operations.

"We were very pleased with the World Cup," said chief executive David Harding.

"Some of the shine was taken off it by Brazil winning and Ronaldo being the top scorer, but in all it was very good."

Slower going

But the bookmaker said that in recent weeks the tables had turned.

"Since the end of the second quarter, the group has experienced a run of less favourable results, with horse racing margins running below management's expectations of the long-term norm," the company said in a statement.

However, it said the bad run was nothing to be too worried about.

"Out of eight weeks, there have been six where the results have been very much to form and so margins have been below what we would normally expect over the long term," Mr Harding said.

"Anyone who knows bookmaking knows this happens from time to time... we fully expect results to even out over the longer-term."

Promising debut

William Hill operates more than 1,500 betting shops and also offers telephone and online gambling.

The company has been one of the few success stories on the London Stock Exchange this year.

Despite the turbulent market conditions, William Hill floated on the market in June and has remained above its opening share price of 225 pence a share.

On Monday afternoon, its shares closed down 21p at 253p.