The rise of online betting continues to boost William Hill after the bookmaker reported a 19% jump in first-quarter profits.

Alongside a "robust" performance from its traditional over-the-counter operations, the group said turnover from online bets exceeded £50 million in a single week for the first time during the quarter.

Mobile device turnover reached £11m in a single week as the launch of the first William Hill sportsbook app in the Apple store gave it access to thousands of new customers.

In the trading update covering the 13 weeks to March 27, William Hill said revenues from wagers placed over the internet and mobile phones jumped 33% year-on-year, with amounts wagered on sporting events up by 31%. In the high street business, William Hill said bad weather in February resulted in 8% fewer horseracing fixtures in the quarter and caused a 2% drop in the amounts wagered in over-the- counter bets. But further growth in machine gaming revenues and a decent run of sporting results for bookies meant retail's profits were 8% higher in the quarter.