LONDON, Aug. 12 (Xinhua) -- Almost a fifth of British young people aged 16 to 24 are so addicted to their smartphones that they spend more than seven hours a day online, the Sunday Telegraph newspaper on Sunday quoted new Ofcom data as saying.

The exclusive analysis for The Telegraph showed that young people in that age bracket are twice as likely as the rest of the population to be online for what is equivalent to over two full 24-hour days a week.

The data also reveals a generational digital divide as just one percent of over 65s and only six percent of 55-64 year olds spend more than 50 hours a week online, compared to the 18 percent of 16-24 year olds, equivalent to more than 1.1 million young people.

Ofcom, the UK's communications regulator, provided the inter-generational breakdown of heavy users after revealing earlier this month that Britons are on average spending a day a week online and check their smartphones every 12 minutes.

Online experts expressed concern that such heavy use of phones, tablets and PCs could be having a negative impact on relationships, productivity and even mental health.

One in seven, or 15 percent, of younger users admitted they were more productive when they lost access to the internet, and one in five, or 19 percent, said they were less distracted.

More than half admitted their devices interrupted face-to-face conversations with families and friends.

Even the oldest of the 16-24 year-olds were just 13 when the iPhone was launched. Now 95 percent of that age group use their smartphone to go online, compared to 70 percent of all adults and just 22 percent of 65 to 74-year-olds.

Young women appear to be more addicted to their smartphones than young men, with texting (53 percent), logging on to social media sites (44 percent) and browsing the web (34 percent) the most popular activity while commuting.

Women aged 16-24 years old on average spend a full hour longer each day on their phones than men of the same age, four hours a day compared to three by the men.

For all adults, the proportion spending over 40 hours online has quadrupled, from 5 percent to 19 percent since the iPhone was launched in 2007. Among 16-24 year olds, it rises to 33 percent. Three-quarters of the age group spend more than a day a week online.

The young generation is more tolerant about using smartphones during activities with family or friends, with just 21 percent saying it is unacceptable while watching TV with others, compared to 41 percent of all adults.

Half thought it was acceptable to check their phone for notifications during a meal compared with just 17 percent of all adults.