Inside the bunker would have been a bomb indicator that would measure pressure waves in the event of explosions.
Meanwhile, a pinhole camera would have been fitted on the top of the bunker which would have recorded the blasts.
Using those readings, the volunteers underground in Scarborough would ring in that information to another bunker, at 20 Group Headquarters in York.
That bunker – much larger than those dotted around the countryside – remains to this day and is now a tourist attraction.
Nestled in the middle of a housing estate, it would have been home to the operations room, to which volunteers in about 70 monitoring posts would send their reports in the event of war.
In the subterranean York HQ, about 60 ROC volunteers would map where the nuclear explosions had taken place, how powerful they were and the impact on towns from after-effects such as fallout.