It's our hidden tragedy: people who live totally alone and who will spend Christmas in isolation, a day like any other. But what are their lives really like?
We experience a day in the life of those who rarely have any human contact. For many, they have little choice. Some, like Derek, find that bereavement in later life brings life challenges which are seemingly insurmountable. Even in earlier years, as for Sarah, a traumatic event means that life can feel solitary even when surrounded by other people.
But there are shafts of sunlight too - volunteers and call centre workers dedicated to helping those in need of company. And for one man, the ballroom offers a route back to happier times.
Presenter: Caryl Parry Jones
Producer: Michael Surcombe.