As you emerge from the Northern Line at Clapham South underground station you can see, about a hundred yards away, a concrete pillbox of a building, on the common but very close to the busy A24. Currently graffiti covered, it marks the entrance to a warren of tunnels deeper than the London Underground lines. This is one of eight locations of very deep shelters, excavated during World War Two. The Clapham South entrance stands surrounded by vegetation encroaching from the common, unlovely and unloved, but what it contains is fascinating.
It is also perfect territory for a crime novel and these shelters feature in all three novels in my Clapham Trilogy, The Midnight Man (2024), A Death in the Afternoon (2025) and Festival Days (coming 2026) set during the years between 1946 and 1951.
The story of the shelters really begins on 1st April 1939, as General Franco declared victory in the Spanish Civil War, the surviving British members of the International Brigade escaped home. They and their fellows had experienced aerial bombardment by the German Luftwaffe in Barcelona, Madrid and Guernica on a scale not seen before. They tried to warn their compatriots about the new nature of aerial warfare but were, largely, ignored. Only in 1940, after the Blitz had begun did the government return to this idea.
Once the Blitz began it was the people of London who decided for themselves that the safest place was beneath the earth, away from the falling bombs and incendiaries. On 8th September 1940 a large crowd broke through the barriers at Liverpool Street station to take refuge on the platforms below. There was debate in government circles as to whether or not to allow this, but it was permitted. Thereafter Londoners began to use the stations of the London Underground as makeshift shelters on a regular basis, taking their bedding down for the night. The direct hit on Bank station, however, which killed fifty-six people, revealed that many of the stations were too close to the surface to provide real safety and the government agreed that deeper shelters were needed.
Ten deep shelters were planned, but only eight were eventually constructed, four south of the river and four to the north, broadly following the Northern line, already one of the deepest underground lines. You can still see the pillbox shaped buildings, with ventilation shaft tower attached at Clapham South, Clapham Common, Clapham North and Stockwell in South London. Deep shelters were also excavated at Goodge Street, Camden Town and Belsize Park in North London, along with Chancery Lane on the Central Line. Those planned for Oval and St Paul’s were abandoned.
London Underground was entrusted with construction and work began. A full-scale model of a section of shelter was erected on Clapham Common, to gain experience of laying the tunnels and fitting them out. It was at Clapham, with three shelters, that a lot of the spoil from the south London shelters, was dumped, creating a twenty-foot-high mound on the Common.
Despite working at a remarkable pace, by the time the work was finished the Blitz was over. The tunnels came into their own, however, in 1944 when German rockets bombarded London. Londoners descended, nightly, to their bunks in the shelter, which also held canteens, lavatories, washrooms and a medical centre. Their overseer, a Mr Copeman (he appears in the novels as the character Owen Philpott) was based at a compound at Clapham South.
After the war ended many of the shelters were used to store government documents. The one at Chancery Lane became the Kingsway Telephone Exchange. The shelter at Clapham South had an extended life, however, which proved fertile ground for this crime writer. In 1948 it was used as a billet for men from the MV Empire Windrush who had no contacts in Britain to go to. They were bussed from Tilbury to Clapham to sleep beneath the earth. The nearest Labour Exchange being in Coldharbour Lane, Brixton they naturally gravitated towards that area. Thus ‘Black Brixton’ was born.
Clapham south shelter today
Subsequently, in 1951, the Clapham South deep shelter got another lease of life – as an hotel. The Festival Hotel housed visitors to the Festival of Britain, accommodating coach parties from elsewhere in the UK. Each guest paid two shillings for a bed (a blanket, pillow and bunk, though women and girls got a sheet too) or three for a bed with breakfast and an evening meal. Although primitive, the accommodation was cheap and it enabled people of more modest means to visit the capital and the Festival. It’s custodian, a Mr Cairns (Abert Foster in the third book), stated at the time ‘It’s a paradise for pickpockets and pilfering.’ He sent all individual visitors, as opposed to groups, to the nearby Cavendish Road police station for vetting before allowing them to stay.
In my novels the shelters are the location for murder. When above ground, away from the busy road, as one walks on the green and pleasant Clapham Common to the restored Victorian bandstand, or around the lakes, it is easy to forget that the tunnels are there. Yet, as the tagline from the first book reminds us, you should ‘Beware the darkness beneath…’.
The London Transport Museum runs regular tours of the Clapham South deep shelter (although you have to be reasonably fit to manage those 180 steps up and down as the shelter is eleven storeys deep). See their website at Discover Hidden London | London Transport Museum