The unusual living arrangement of Shirley Denny and Peter Lawrence has raised eyebrows among friends and neighbours over the past two decades.

But today the couple, who have shared their lives but not their homes for 23 years, are part of a growing trend of people challenging the assumption that being in love must lead to cohabiting.

New research estimates that there are now as many as two million couples who, despite being in a committed relationship, live separately. The number of couples who live apart together (LATs) is now roughly the same as those who live under the same roof.

For Ms Denny and Mr Lawrence, whose attempt to live together failed dismally after just three months, the decision to live apart has been a triumph. It has, they insist, kept their relationship fresh while providing the ideal environment in which to bring up their four children (two from each partner’s previous relationship).

To underline the point, they got married last year.

Ms Denny, 55 and Mr Lawrence, 61, are defined as “gladly apart” LATs by Sasha Roseneil, Professor of Sociology and Gender Studies at Leeds university and author of the report On Not Living With a Partner.

Based on interviews with LATs in Yorkshire, she focused on why devoted couples should want to live alone and found that most had made a conscious decision to keep their domestic lives separate.

“They have arrived at this point sometimes because a previous cohabiting relationship has broken down, or they do not want to impose a new partner on children from a previous relationship,” she said.

She found only a small minority, the “regretfully apart”, are forced into it by competing work commitments or family responsibilities.

Professor Roseneil identified a third group, “undecidedly apart”, who, while committed to one another, did not find themselves on the path towards cohabiting.

Her findings bear out the first research on British LATs conducted by the University of Oxford research fellow John Haskey, who in 2005 estimated that up to two million couples were living in separate homes.

While living apart is popular among younger people, his study found hundreds of thousands of older couples between the ages of 35 and 59 were also choosing separate living. He estimated that up to 14 per cent of 50-to 59-year-olds were LATs. Using data from overseas, Professor Roseneil said that it was “highly probable” that LATs are on the increase.

In Sweden, which has witnessed similar trends in divorce, marriage and people living alone as Britain, the number of LATs has risen from just six per cent in 1993 to more than 14 per cent at the last count five years ago.

Other experts agree that LATs are now part of the social landscape.

“When you hear about a couple choosing to live apart, no one thinks that’s odd any more. They say that sounds fine, or even that it sounds like a good idea,” said Penny Mans-field, the director of One Plus One, a charity, which studies couples and family relationships.

However, she believes that there could be some serious implications for social cohesion if increasing numbers of couples live apart.

“When you have a large number of self-sufficient family units, that is good news for society. The more fragmentation you have the less good it is. The rise we have seen in low-grade mental illness is increasingly linked to this sort of fragmentation,” she said.

Distant stars

Woody Allen and Mia Farrow lived in different homes on either side of Central Park, New York

The novelist Margaret Drabble and the biographer Michael Holroyd have been married for 24 years but still live in separate London homes

The actress Helena Bonham Carter and the director Tim Burton have one son but two houses, next door to one another in Hampstead, North London

The Booker prizewinner Arundhati Roy lives in a rooftop Dehli flat while her film-maker husband Pradip Krishen lives in a separate house in the city

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