Bookmaker William Hill saw its quarterly profit tumble after suffering the biggest loss-making week in the firm’s 81-year history.

The company, which runs 2,361 betting shops, said wins by Premier League football favourites meant it racked up a weekly loss of £14 million (€19.6 million) in the middle of January.

Operating profits for the three months to the end of March were down 19 per cent to £16 million (€22 million), with the result also reflecting the £20 million (€28 million) impact of December’s introduction of a point of consumption tax and the March increase in machine gaming duty to 25 per cent from 20 per cent.

Chief executive James Henderson said: “Gross win margins were below our expected trading range for what is typically a stronger quarter, impacted by — amongst other things — our largest ever loss-making week, in week three.”

He added: “Looking forward, as the end of the football season draws closer, we have not as yet made up the shortfall arising from the £14 million loss in week three.”

William Hill has upgraded its online business in recent years and said its mobile betting sales jumped 48 per cent during the period, and now accounted for 37 per cent of all gaming revenues.

It added that sales at its online casino games were up 10 per cent during the period and bingo was up 8 per cent, although poker revenues slumped 32 per cent.

The firm said it closed 108 shops last year, as a response to the planned increase in machines games duty. However, during the last period it opened one shop and closed two outlets.

The firm said that in March the government changed planning regulations so that bookmakers have to seek additional permission to turn existing commercial premises into betting shops.

It said: “We do expect to see a short-term impact on shop opening numbers.”

The industry faces further political uncertainty as the Labour party’s manifesto includes the proposal to give local authorities the ability to reduce, or ban, gaming machines from betting shops in their area.