Crouching in a Flanders trench in November 1917, 21-year-old Walter Butler addressed a field service card to his fiancee Amy to let her know he was safe.

She never received it. After the war Butler returned to England and the pair married, moved to London, and had a daughter. Eventually they divorced; Amy returned to her family home while Walter remarried and led a career as a builder. She died in 1974 at age 81, he four years later at 82.

In February 2007, the card arrived. Their daughter, now an 86-year-old grandmother, received it.

“I am quite well,” it said. “Letter follows at first opportunity. I have received no letter from you for a long time.”