It's a Sunday evening when Cheshire Police get a call from Mark Moran of the Veterans Association, a charity. The charity's founder, former soldier Mark Smith, has not been seen for almost 24 hours, following an argument with his wife Denise.

Eighty-three-year-old John only turned his back for a moment while buying some parsley, but that was long enough for his wife Sheila, who has dementia, to disappear from his sight and into the busy streets of Gloucester town centre at lunchtime.

It's late at night when 25-year-old Oli calls Gloucestershire Police. His father, Michael, has missed an appointment with his mental health worker, and no-one knows where he is. Michael is known to be suffering from paranoid schizophrenia.

Thirty-seven-year-old Aaron hasn't been seen for two months and is reported missing by the Gloucester homeless healthcare centre that usually treats him. Officers scour the streets and homeless shelters of Gloucester but can find no trace of him.