In 1938 it became obvious that a major war was inevitable. Construction of ARP (Air Raid Precaution) shelters was stepped up both in Britain and in Germany.
In Britain, the Civil Defence Act 1939, made it compulsory for employers at mines, factories and commercial buildings in ‘specified’ areas with more than 50 employees to provide air raid shelters.
The ICE Air Raid Committee produced a report in 1938 which heavily influenced the Government advice provided in ARP Handbook no. 5 issued in June 1939.
Air raid shelters took many forms and sizes from those designed for a single person to those for over 11,000 people and a variety of materials were used in their construction including concrete, steel and timber.
The job book of GKN (Guest, Keen and Nettlefolds), specialists in the design and supply of reinforcement, shows that in early 1939 two-thirds of civil engineering output was air raid shelters for individuals, companies and local authorities. By the outbreak of war output was virtually 100% war related including airfields, aircraft factories, decontamination centres, first aid posts, mortuaries and of course more air raid shelters. Occasional exceptions could be found including improvement works to two pubs. The typical price per shelter was £17.
Many contractors were involved including Henry Boot, Bovis and John Laing. The shelters were categorised, with type C being the most popular
Air raid shelters in Germany
At the same time Germany was also constructing air raid shelters. Continental building construction meant that a greater number of basements were available as air raid protection.
In the UK, basement space was less common in houses but large buildings such as department stores and factories converted large basement spaces, strengthening them with tubular steel or wooden struts .
Government advice for shelters
As the war progressed, Government policy changed. It was thought that the chances of injury due to a direct hit were less than the danger of being hit by shrapnel. It also seemed less likely that larger bombs would be dropped due to the greater risk of heavy aircraft being brought down by anti-aircraft fire. Lighter incendiary bombs were used instead.
Communal street shelters
In March 1940, the Government started a a programme of building street communal shelters. They were to built by private builders under supervision of Government inspectors and surveyors.
Between 1940 and 1942, consulting engineer Ove N. Arup advised on street and basement air raid shelters for the Metropolitan Borough of Finsbury in north London. The Ove Arup collection in the ICE archive includes a large file of bills of quantities and correspondence between Arup, and Messrs J. Lawson and Col Ltd, John Lewis Building, and Holland, Hannen and Cubitts Ltd for basement and street shelters in Finsbury Park.
The street shelters were built with brick walls and a concrete roof and did not perform well. The walls would be shaken during raids and could fail allowing the concrete roof to fall on the people sheltering inside. Although the designs were improved, the public had lost confidence and preferred not to use them.
Ove Arup also produced designs for various reinforced concrete mass public shelters including some holding up to 12,800 people. The larger designs were deep shelters with double-helix ramps allowing people to enter quickly and intended to be used as multi-storey underground car parks after the war. The shelters included air conditioning, sleeping accommodation and toilets.
The Arup collection includes his original drawings which were reproduced in his report, prepared by the Metropolitan Borough of Finsbury entitled ‘Design, cost, construction and relative safety of trench, surface, bomb-proof and other air raid shelters’.
Unfortunately Government did not favour very large shelters, preferring small domestic shelters and Arup’s designs were considered controversial and were never built.
But Arup was not the only engineer thinking large, Iorys Hughes – one of the engineers behind the Mulberry Harbour – also prepared designs for large shelters.
As in Germany, one idea was to use buried tubes, as described in the Cement and Concrete Association’s Air raid leaflet no. 3. Unsurprisingly, these were to be made of concrete rather than corrugated iron.
[ICE Library ICE 194-CEMARS]
This design could be scaled up to create large public shelters. Precast concrete tubes were to be laid like sewers and equipped with ventilation and gas-filtration equipment.
[ICE Library ICE 194-CEMARS]
The Adcock and Stroyer collection includes correspondence relating to provision of air raid shelters for residents in Stepney.
When designing shelters there was a delicate balance between safety and cost to be considered. Speed of construction was also a deciding factor. Trenches and various types and sizes of shelter were tested and cost plotted against protection provided.
Using Underground stations as air raid shelters
Although during the First World War underground stations had opened their doors out of hours to provide shelter from the Zeppelin raids, as early as 1924 the government decided that in future this would not happen so as not to impede traffic and because of the risk of disease spreading. Churchill was not in favour of this policy but went along with it initially at a Cabinet meeting on 13th September 1940. However eight days later The Times reported that the Aldwych Branch up to Holborn would be available as a shelter.
Work began in earnest to convert a section to a shelter including bunks on the platform and running lines. Westminster City Council rented this section from London Passenger Transport Board (LPTB) for £300 per year. Tickets were issued to users to prevent overcrowding and guarantee a bunk or floor space.
Not that use of underground stations was always a guarantee of safety and many lost their lives whilst sheltering. Major fatalities occurred at Balham, Bounds Green and Bank. Bethnal Green was not opened to traffic until after the war but was in use as a shelter. Sadly 173 people lost their lives during a crush to enter the shelter in 1943. A plaque commemorates this disaster at the station. Flooding was also a concern at stations used as shelters since a damaged tunnel near the river could result in large parts of the system being flooded This issue was only solved by the installation of flood doors at strategic points. Until then the public were not informed of the risk.
The railways were always a strategic target and major damage was inflicted on London’s railway system for example Hungerford (half the bridge demolished), Victoria on the Kent side (the repair work is still visible), Waterloo and Cannon Street. The key point here must surely be the heroic efforts of civil engineers and railway workers to get services running again often in a matter of hours.
In total 79 stations were fitted with bunks. In the early blitz London Underground was sheltering 177,000 people every night, with a further 17,000 people using redundant tunnels. The shelters were supplied with first aid facilities and equipped with chemical toilets. 124 canteens opened in all parts of the tube system