But those with strong social networks interviewed for the study were 30% more satisfied with their lives than those without, the conference in Stratford-Upon-Avon heard.

Research author Dr Oliver Robinson said: "Having family around is less of a positive thing than we would have initially imagined.

"But then when we interviewed people it made sense."

He said retirement was supposed be a time when people were finally able to enjoy their own time, free from the constraints of going to work.

"Having grandchildren can be great but often what comes with that is substantial childcare responsibilities. It's lovely but it is a tie," the senior lecturer in psychology added.

"There was no difference in life satisfaction rates between individuals with and those without grandchildren."

'Online dating'

He said many retirees were fed up with being "constantly at the beck and call" of their children for childcare.

And there were many retired people without children who were bored listening to their friends with grandchildren cooing over them, he added.

Research for the pressure group Grandparent Plus suggests a quarter of families call on grandparents for childcare.

The study also concluded that retired people who were married or in long-term relationships were happier than single individuals.

And couples who were both retired were happier than partners of those still working.

Dr Robinson said older people appeared to be making use of web-based social networks and online dating services to boost their social networks.