David Swainston joined 15 Group (Cambridge) of the Royal Observer Corps to further his interest in aircraft but a lack of openings in aircraft recognition led to him working with the Centre Team plotting aircraft movements. Later, changing national priorities led to a volunteer post at Oakington Airfield.  Here he practised with his team identifying the position and strength of nuclear explosions from an underground observation post and then feeding radiation measurements back to Centre over a period of time. Life in the very small bunker is described, including DIY painting of the post’s concrete walls.

He recounts many colourful stories of the amazing lack of co-ordination between ROC operations and those of the Army and RAF from whose sites they operated. For instance a 24-hour “shut down exercise” was interrupted by a senior officer at the airfield who was completely unaware of the exercise.