Britain's young people have bought into the cohabitation "myth" as latest figures suggest that nearly half of today's teenagers will never walk down the aisle.

In an analysis of new data from the Office for National Statistics, the Marriage Foundation found that marriage is virtually disappearing among the under-25s as more and more couples choose to live together without bothering to tie the knot.

Whereas in 1970, 81 per cent of women and 62 per cent of men had married by the age of 25, today only 8 per cent of women and 4 per cent of men in the same age category have done so. 

If the current trend continues, the Marriage Foundation predicts that 57 per cent of today's teenage girls and 55 per cent of teenage boys will eventually marry. 

This is well down from the 91 per cent of women and 86 per cent of men currently in their 60s who have been married. 

People are also increasingly waiting until they are older before getting married, with the 35 per cent of men and 29 per cent of women getting married after the age of 30.  This compares to only 11 per cent of men and 6 per cent of women who did the same back in 1970. 

At the same time, the proportion of people marrying before age 30 has fallen from 85 per cent of men and 91 per cent of women half a century ago to 21 per cent of men and 30 per cent of women today. 

The Marriage Foundation's Harry Benson said that while many young people still dream of a lasting relationship with their soulmate, the trend towards cohabiting makes this harder to achieve. 

"The introduction of widely available birth control in the 1970s made it safe for the first time in history for couples to sleep together or live together without the consequence of pregnancy," he said.

"But as cohabitation became more normalised, so marriage has become ever more optional. Although habits may have changed, human nature has not. If we want reliable love, we still need clear decisions, signals and social affirmation of our plans for the future - that's what marriage provides.

"However, early cohabiting without a clear plan for the future leaves many couples in ambiguous and ultimately unstable relationships. As those relationships fail, it delays any eventual marriage for some and means others miss out altogether.

"Teens still want the dream. The irony and tragedy is that they are sabotaging their own chances by moving in too quickly without a clear plan of where they want to go."

Sir Paul Coleridge, Founder and Chairman of the Marriage Foundation, said young people had "bought into the myth that informal cohabitation delivers the same long term security for their families when it is three times more likely to end and almost certain do so before their children become teenagers".

"The good news is that for those who do marry (about 245,000), divorce rates have been on a consistent downward trend. Those who now marry are doing better than ever," he said.