In August 1918, he volunteered for military service and was sent to the front in the First World War as a lieutenant in the 3rd Battalion, South Lancashire Regiment.

She wrote in her autobiography about her first encounter with her husband-to-be: "I noticed his bright blue eyes, his casual elegant clothes and his polite way.

He served as a lieutenant in the East Yorkshire Regiment and later was part of the British Expeditionary Force deployed in France.

Davis remained with the army until almost the end of the Second World War, with tours of duty in North Africa and Northwest Europe.

[5] This clause led to Davis being cast as the mild-mannered librarian Mr Stringer in the four adaptations of Agatha Christie novels featuring Rutherford as Miss Marple in the early 1960s.

Reportedly, his mother was the main reason for the long engagement because she was adamantly opposed to having Margaret Rutherford for a daughter-in-law, referring to her when talking to her son as "that older actress woman you have been seeing over the years."

Towards the end of her life, Rutherford was diagnosed with Alzheimer's disease and Davis tended to her throughout a long and distressing illness.

[8][9][10] Davis died peacefully in his sleep in Chalfont St Giles, Buckinghamshire in August 1973, 15 months after Rutherford's death.