Britons check their phones every 12 minutes while the number of voice phone calls fall for the first time, the latest report from Britain's telecoms regulator Ofcom reveals Thursday.

According to the Ofcom digital dependency report, a fifth of British adults now spend 40 hours online each week, more than the average time spent at work. Overall, people claim to spend an average of 24 hours each week online, double the amount of time spent in 2007.

The annual communications market report also found that in contrast to just 10 years ago, most people now say they need and expect a constant internet connection wherever they go, with 64 percent of adults describing it as an essential part of their life.

About 75 percent of smartphone owners consider using a mobile for phone calls is important, compared with 92 percent who think using the device for internet browsing is important.

Two in five adults first look at their phone within five minutes of waking up, rising to 65 percent of those aged under 35.

But while there are now more mobile phones in Britain than people, the number of actual calls from them has fallen as messaging apps such as WhatsApp increase in popularity.

"Over the last decade, people's lives have been transformed by the rise of the smartphone, together with better access to the internet and new services," said Ofcom's director of market intelligence Ian Macrae, "Whether it is working flexibly, keeping up with current affairs or shopping online, we can do more on the move than ever before. But while people appreciate their smartphone as their constant companion, some are finding themselves feeling overloaded when online, or frustrated when they're not."

Around 15 percent people surveyed say it makes them feel they are always at work and more than half admitting that they had a negative impact on face-to-face conversations with friends and family.