The happiest people live in big families, according to the latest official research into the causes of contentment.

The happiness measures – backed by David Cameron as a means to guide government policies – found that more than two thirds of people who live in families headed by a couple with three or more children consider themselves to be happy most of the time.

They also show that members of large families say they are more satisfied with their lives than others and that they think they have stronger personal relationships than most people.

Evidence of the link between big families and happiness comes at a time when parents are having fewer children and the number of children growing up with large numbers of brothers and sisters is at an all-time low.

Happy families: Happiness measures found that more than two thirds of people who live in families headed by a couple with three or more children consider themselves to be happy most of the time (file photo)

According to a count conducted by the Office for National Statistics, the decline of marriage and the pressure on women to go out to work have contributed to a drop of the proportion of families with three or more children to around one in seven. Two decades ago 17 per cent of parents with children had three or more, compared to 14 per cent now.

The connection between large families and happiness was made by the EU’s statistics arm Eurostat in a major study of the results of quality of life surveys carried out across the continent.

It found that 66.8 per cent of homes with two adults and three children said they had been happy all the time or most of the time over the four weeks before they took part in the survey. Smaller families with one or two children recorded happiness levels just under the two thirds mark.

‘Generally two adult households, in many cases couples, were happier than people living on their own,’ the Eurostat report said.

‘Households with children were the happiest, with the exception of single parents who report rather low happiness levels.’

By contrast the least happy people were women aged over 65 who lived alone, among whom more than one in five said they rarely felt happy.

The 278-page Quality of Life report said families with two parents and three or more children also reported the best levels of satisfaction with their lives. Some 28 per cent said they were highly satifisfied, more than double levels recorded by single working-age men, and nearly double those of single parents.

A similar pattern applied when people were asked about the quality of their personal relationships. Some 41 per cent of families with two parents and three or more children reported high levels of contentment with relationships.

Higher relationship satisfaction levels were recorded by couples of all ages, and by single women over 65, but there were also low levels of happiness with relationships found among greater numbers of single over-65 women.

Smiles all round: The evidence comes at a time when couples are having fewer and fewer children and the number of children growing up with large numbers of brothers and sisters is at an all-time low

The report said wealth, health and education were important for happiness, and that unemployment was closely linked with low life satisfaction. It found self-employed people tended to be less satisfied with their personal relationships, probably because many work unsocial hours which limit their social lives.

Retired people, by contrast, are happier with relationships. The report said this may be a result of ‘greater time availability that allows them to pursue opportunities to develop and maintain personal relationships.’

The happiness measures, which are based on scores out of 10 given by people asked a series of questions about their well-being, were introduced in Britain in 2010 with personal encouragement from the Prime Minister. They are intended to give an alternative to traditional measures of how well people are doing, and to give better guidance to ministers and civil servants.

Households with children were the happiest, with the exception of single parents who report rather low happiness levels.

The EU report said happiness is not directly linked to wealth.

‘Luxembourg, Norway and Switzerland show high values of overall life satisfaction but they are not as high as a potential relationship between Gross Domestic Product and average life satisfaction would imply,’ it said.

‘However, other factors may be at play as well. On the other end of the scale Bulgaria shows even lower life satisfaction than would be expected from its low GDP. The GDP of Romania is comparable to that of Bulgaria but residents of Romania rate their life satisfaction much higher on average than their Bulgarian counterparts.’

Britain scored above-average levels of overall life satisfaction – 7.3 out of 10 compared to an EU average of 7.1 – a finding that may be linked to higher numbers of large families in England.

Only six of the 28 EU countries have higher proportions of families with two parents and three or more children, despite the falling proportions in Britain. Large families are increasingly rare because of the movement of millions of young women through higher education and into careers, and because the decline of marriage has led to delayed childbirth and smaller families.

Married couples, according to recent UK figures, have an average of 1.79 children, while cohabitee parents average 1.62.