The phones unseated laptop computers as the most popular device for using the Internet, with the larger devices falling from 40 per cent of online connections in 2014 to 30 per cent in 2015.
The multi-purpose handsets however have risen from 23 per cent last year to 33 per cent this year, with younger users the main driver behind the change, said Ofcom's 2015 Communications Market Report.
The change was attributed to the expansion of high-speed 4G data networks by the report, which allows users to watch video on the go. It also found that two-thirds of adults now have a smartphone, up from 39 per cent in 2012, and the amount of time we spend using them to go online has risen to one hour and 54 minutes per day.
Jane Rumble, director of market intelligence at Ofcom, said: "You can see these devices are becoming more and more an important vital hub of information and communication throughout the day, with smartphone owners spending...