About 26 million Britons visited an adult website or app in September 2020, with the largest, Pornhub, attracting around a third of online adults. This means half of all British men and 16 percent of British women, Ofcom said in its annual survey of the nation's online habits.

Ofcom said it had started research on adult content as part of its new duty to regulate UK-based video-sharing platforms and as it prepared to take on responsibilities for online safety.

The average time spent online on smartphones, tablets and computers increased to three hours and 37 minutes a day, nine minutes up on 2019 and more than an hour longer than in Germany and France, and 30 minutes more than Spain.

Another one hour and 21 minutes were spent watching services such as Netflix and BBC iPlayer on TV sets, Ofcom said.

Social video sites and apps were used by almost all (97 percent) of UK adult internet users, and by 93 percent of 3–4-year olds, the survey showed.

Young adults were the heaviest users of social video, with 18-24s spending an average of one hour 16 minutes per day on YouTube in September – an increase of 11 minutes since 2019.

But its rival TikTok, a video-sharing social media site, saw the biggest jump in both users and usage during the pandemic.

Its users rose from three million in September 2019 to 14 million by March 2021, while 18-24s more than doubled their time spent on the platform in the year to September 2020, rising from 17 minutes to 38 minutes.