Oxford University psychologists found husbands and wives who kept in touch using social media had less satisfying marriages.

London - Social networking is ruining Britons' sex lives because they are wasting too many evening hours online.

People are going to sleep 90 minutes later than 10 years ago - because they sit in bed using Facebook and Twitter, it has emerged.

A typical adult now drops off at midnight, compared with 10.30pm ten years ago. Nearly half of us – 46 percent – spend those 90 minutes going online under the covers.

And 15 percent said this has led to them having less sex.

On average we sleep for seven and a half hours less a week than a decade ago – equivalent to 360 hours a year.

Browsing the web is the most popular bedtime web habit, luring one in four of us. Some 15 percent catch up on TV shows, while 13 percent go on social networks after they’re tucked up.

Two-thirds of under-30s in the survey by price comparison website broadbandchoices.co.uk admitted to tweeting or using Facebook in bed.

Dominic Baliszewski, telecoms expert from broadbandchoices, said: “We're not surprised people are turning on for the night, rather than turning in.

“Broadband has become an essential utility - with so much entertainment available online and so many devices with which to enjoy it, people are using every minute of their free time to get online.

“There has been an explosion of broadband providers over the last 10 years and services are improving all the time, which has contributed to an 'online all the time' culture.”

One night-time surfer, Debbie Fox, 28, from Essex, said “I often work late and by the time I've got home and had something to eat I've usually missed anything that I might have wanted to watch on TV and it's too late to call my friends.

“I always end up taking my laptop and phone to bed with me and make the most of all that's available online in the comfort of my bed - I can see what my friends have been up to and watch catch up TV when it suits me.” - Daily Mail