Film about a woman with dementia and her son. What is it called?

It's a British one off pogramme, about an elderly woman and her son.
It's starts after the woman has died, and the son is looking around
his Mothers house reminiscing and then the film goes back to the
memories and the events leading up to his Mother's dementia, her
subsequently going into a nursing home and her death. It was
heartbreaking and I would really like to see it again.