Physically, being lonely is the equivalent of smoking 15 cigarettes a day in terms of causes of early death.

A third of people in their 50s or above, and almost half of those over 80, suffer from feelings of loneliness, a study in the UK has found.

Women were also more likely to experience loneliness than men, the report released by the Office for National Statistics (ONS) found.

Laura Ferguson, director of the Campaign to End Loneliness, said the condition was more dangerous than many imagined.

She said: “Physically, being lonely is the equivalent of smoking 15 cigarettes a day in terms of causes of early death.”

Isolation can also contribute to depression and Alzheimer’s, she added.

Ferguson went on: “Situations like becoming widowed or bereaved can contribute to feeling lonely, especially at a time when you’re reaching an older age, like 80 plus.

“You might be losing mobility and losing people around you.”

The figures showed some 39 per cent of women aged 52 and over said they sometimes or often felt lonely compared to 27 per cent of men, the English Longitudinal Study of Ageing showed.

Those aged 80 or over were also more likely to feel lonely, with 46 per cent saying they felt lonely some of the time or often, compared with 34 per cent of all those aged 52 or over.

Widows were the most likely to feel isolated of any group, with 63 per cent reporting feelings of loneliness.

Ferguson added that women in their 50s may be at higher risk of loneliness because of a combination of increased rates of divorce, empty-nest syndrome and being less likely to have worked in the same place for as long as men of the same generation.

“A lot is already being done to combat loneliness, and the best thing that can be done now is not remove the activities that are already there for people who feel lonely, from singing groups to lunch clubs or anything they are interested in,” she said.

The study also found that people with conditions which limited daily activities were more at risk of feeling isolated than those who were ill but more physically able.

People who said they were rarely or never lonely were the more likely to be satisfied with their lives (with 89 per cent saying they were satisfied), compared to those who said they were often lonely (38 per cent).

Michelle Mitchell, charity director-general at Age UK, said cuts to local authority budgets would only exacerbate the problem of loneliness.

She said: “The ongoing crisis in the provision of social care means that large numbers of older people are missing out on essential care that could make the difference between staying active and becoming isolated. Feeling lonely not only makes us miserable, it increases our risk of developing serious mental and physical health problems.

“We can all do our bit to help fight this growing problem by making time for older relatives and checking in on older friends and neighbours that we know.”