It was in September 1935 that the British prime minister, Stanley Baldwin, published a circular entitled Air Raid Precautions (ARPs), inviting local authorities to make plans to protect their people in event of a war. Although notorious for so often being last to do things, Peterborough appears to have been on the ball here and began to implement ARP soon after the outbreak of the conflict. It was on this day that the London Brick Co. at Fletton stated that all of its precautions were completed and, in all the works at Fletton, some form of protection was available. A number of old tunnels with 15ft to 20ft of earth above them had been turned into shelters with 'baffle walls' at the ends to make them safe from blasts and flying debris. Where there were no convenient tunnels they had built brick-lined trenches, covered them with sheets of corrugated iron and then piled quite a few feet of earth on top. All protective places had seating, a water supply, toilet facilities and emergency lighting. At the museum in Priestgate, the old cellars - dating back to the sixteenth century - were brought into use as very effective air-raid shelters. (Grey, David, Peterborough at War 1939-1945, David Grey, 2011)
Taken from The Peterborough Book of Days by Brian Jones, The History Press, 2014.