Hundreds of thousands of elderly people are left isolated because their grown-up children live too far away, warns a charity.
These elderly parents depend on phone calls from their children for social contact, says a report from the WRVS.
Even though a large majority of over-75s say they are lonely, the report says, these elderly people would not admit this to their own children.
WRVS head David McCullough says this shows "the state of the modern family".
The report from the WRVS, formerly the Women's Royal Voluntary Service, describes how "fragmented" family life in the UK can leave older people stranded with little contact from their own children.
The report estimates more than 360,000 older people have children too far away and "too busy to see them" - a problem that is likely to be regretted as much by children as their parents.
These children are still in touch with their parents - as the report says about a quarter of older people speak to their children every day.
Children move away to work - and the report says insecurity over jobs and pressure on time mean older parents can see less of their family than they would like.
One in 10 older people with children do not have family within an hour's drive of where they live.
Among these parents, living at a distance from their children, half only have visits from their children once every two to six months. There are 15% of such parents who only see their children once a year.
Loneliness is a widespread problem among older people, says the report, and the absence of regular visits from children is an important factor in this sense of isolation.
But almost two-thirds of old people who feel lonely say they would not tell their children because they would not want to "bother them".
Men are particularly at risk of social isolation, says the report. About two in five older men only have one or two face-to-face conversations per day.
In a rather bleak view of family life in the run-up to Christmas, many older people will depend on television as their main form of company.
Almost a quarter of a million older people are expected to spend Christmas Day on their own.