The growing popularity of internet gambling is costing firms nearly £310m each year, a study has calculated.

Business and technology consultancy Morse surveyed more than 1,000 office workers in the UK.

They found that almost a third (30 per cent) said they had placed a bet online during office hours or knew a colleague who had.

Of those questioned, the gambling culprits were most likely to be men (38 per cent) and almost half (46 per cent) were aged 25-34.

According to Philip Wicks, consultant at Morse, this report clearly shows the huge productivity strain gambling at work has on businesses, and highlights the need for employers to focus on enforcing acceptable internet usage.

"Many employees have unmonitored access to the internet and the fact that they can now follow most sporting events online, coupled with the rise of internet gambling websites, has tempted people to place a 'quick' bet online," he said.

"However, these bets all add up and can greatly impact businesses productivity. With online gambling set to rise by 22 per cent this year, it is clear businesses can no longer turn a blind eye to their employees' recreational activities.

"Instead they must look at methods that will control this addiction, starting with creating an internet usage policy that must be adhered to and enforced."

The research also revealed that office workers who gamble online are spending 11.6 per cent of their average weekly salary on online gambling.

This is compared to the average UK household spending 6.4 per cent of their weekly wage on fresh vegetables and 5.2 per cent on fresh fruit.

The most popular website amongst office workers that gamble online is the National Lottery, with 70 per cent admitting that they have placed a bet online.