The airman, Colin Fredrick Chambers, died in March 1943 when his Halifax DT 620 plane was shot down over the Danish coast after having dropped weapons for the resistance movement in Poland.
All the soldiers died in the crash, with the then 28-year-old Chambers washing up on Swedish shores entangled in parachute ropes.
He was buried with military honour at a church graveyard in Fjelie, southern Sweden.
“Throughout all these years, someone has been putting flowers on the grave – and we have no idea who it is,” said church head Krister Hagman of the Bjärred congregation to The Local.
“When the man’s UK relatives visited the burial site for the first time in spring, they were astonished that someone had taken all the trouble. There were fresh flowers and a ribbon with text.
“They naturally wanted to know more, and plan to give thanks to the unknown person, so they wrote us a letter asking if we knew anything.”
In response, the church put out a notice in their parish paper asking for the mystery well-wisher to come forward, however no one has owned up yet.
“We’ve had a lot of calls, but mostly from newspapers wanting to know more. People are certainly interested,” said Hagman
While Hagman confesses he doesn’t know personally who is behind the flowers, he has agreed to get on board with contributions of his own.
“We’ll be adding our own flowers to the gravesite now too, in honour of the fallen soldier,” he said.