https://www.youtube.com/watch?v=DTnTPUVlHUU
It is Britain 1943 and small children are being blown up by some item they find in the countryside.
The story opens with the lead character, a specialist in bomb disarming and his group, trying to retrieve one of these devices, which they think are being dropped by the German planes, flying over England.
There is a side story of the office politics that is occurring in the upper management level.
Excellent BBC Saturday Night broadcast. I think the audiobook is actually done better than the movie. The movie has a slightly different ending.
This novel was also made into an excellent movie in 1949, but the movie is hard to come by.
Movie - the plot is a bit slow at times. The great British actor, Jack Hawkins, has a small part in the movie.
https://bnwmovies.com/small-back-room.html#plot