Some 28% of British adults feel lonely at some time, according to a survey carried out by BBC Radio 5 live.
The poll, of 2,000 people, indicated that 7% of all adults and 10% of those aged over 65 expect to spend Christmas mostly on their own.
Men were more likely to say they would spend Christmas alone, as were those from poorer backgrounds.
A spokeswoman for the Campaign to End Loneliness described the findings as "very concerning".
The study, carried out by the BBC and Comres, suggested:
28% of adults say that they feel lonely at least some of the time
33% say they feel left behind by new ways of communicating and 85% prefer speaking to friends and family face to face
65% think they should do more to help family, friends and neighbours who are lonely
18 to 24-year-olds are nearly as likely (30%) to feel lonely as those over 65 (31%)
Laura Ferguson, director of the Campaign to End Loneliness, emphasised that "loneliness is not just experienced at Christmas, so we all need to support people year round".
The charity advises that loneliness can be transient - coming and going at certain times - or chronic, when someone feels lonely all or most of the time.
Risk factors
Loneliness can be felt at any age, but as people get older, risk factors that might lead to loneliness begin to increase and converge.
Risk factors include but are not limited to:
Poor health
Lack of public transport
Loss of mobility
Lower income
Bereavement
Fear of crime
Retirement
Source: Campaign to End Loneliness
Grey line
To coincide with the publication of the polls findings, the BBC has produced a series of programmes and interviews exploring the circumstances of people who feel lonely and how they have addressed it.
Speaking to 5 live, 29-year-old Jaabir described it as "a gut-wrenching feeling - you have a void that nothing can fill".
'Too exhausted to go out'
"Going back to work was hard. Everyone was supportive and welcoming, but I had been caught in the cancer bubble.
"I didn't know anyone very well and used all my energy at work. So when I was not at work I was too exhausted to go out and meet people or do any of the things I enjoyed doing."
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