Thanks for the links. One reads: "They may have been Stanton Shelters installed by Courtaulds in 1939 to protect their workforce from the Luftwaffe." I take Stanton to refer to Stanton & Staveley, whose namess still appear on countless steel street manhole covers. Wondering as to why a steel manufacturer's name was connected with concrete air raid shelters, I further found that:
"
Stanton air raid shelters were manufactured by the Stanton Ironworks Co Ltd near Nottingham
(the iron connection is in the mould pattern). They could be built to any length but usually consisted of 18 precast concrete arched-shaped units (each one in two parts), bolted together to form a standard (after 1941) Air Ministry shelter for 50 men. The entrance was often brick-lined with concrete steps (where required) and the rear unit had an emergency escape hatch. They are often above ground or semi-sunk but for concealment purposes there were covered by a layer of earth and turf."
The emergency escape hatches mentioned can be seen in some photos. I had never realised air raid shelters were constructed to such a large size.
