The Civil War Comes to Hampstead Heath
When the English Civil War erupted in 1642, Hampstead found itself on the frontline of London's defences. The village, perched high on its sandy ridge overlooking the capital, possessed an obvious strategic value that neither Royalist nor Parliamentary commanders could ignore. The Heath's elevated position offered commanding views south towards the City of London and north towards the approaches from the Midlands, making it an ideal site for military observation and, if necessary, a defensive stand against any force marching on the capital from the north.
Parliamentary troops were stationed on the Heath throughout much of the conflict. A series of earthwork fortifications were constructed along the high ground, part of a broader ring of defensive works encircling London that Parliament ordered built in 1643. These Lines of Communication, as they were known, stretched for some eleven miles around the capital, and while the main fortifications ran through Islington and Tottenham, the Heath served as a natural northern outpost. Local militia companies drilled on the open ground, and Hampstead's inhabitants — many of them sympathetic to the Parliamentary cause, as the village had long attracted dissenting religious communities — found themselves hosting soldiers in their homes and barns.
The parish records from the 1640s reveal the strain that military occupation placed on the small community. Entries document payments for quartering soldiers, the requisitioning of horses, and the damage done to fields and hedgerows by encampments. The churchwarden's accounts note expenditure on powder and shot for the trained bands, the local militia units that formed the backbone of London's defence. One entry from 1643 records the cost of repairing a fence broken by "the souldiers in their exercise upon the Heath," a modest but telling detail that speaks to the everyday disruptions of wartime life in a small village suddenly thrust into military significance.
Though no major battle was fought on Hampstead Heath itself, the village did not escape the conflict's violence entirely. Skirmishes between Royalist raiding parties and Parliamentary patrols occurred in the surrounding countryside, and the Heath's roads — particularly the route north through Highgate — were vital supply lines that needed constant protection. The watchtowers erected on Parliament Hill, the highest point of the Heath, allowed sentries to scan the horizon for approaching forces, a military use of that famous viewpoint that predates its more peaceful role as a spot for Sunday afternoon strolls by several centuries.
Napoleonic Fears and Victorian Volunteers
The threat of French invasion during the Napoleonic Wars brought military activity back to the Heath in the early nineteenth century. Although Napoleon's Grande Armée never crossed the Channel, the fear of invasion was very real, and communities across southern England prepared for the worst. Hampstead was no exception. A beacon was maintained on the high ground, ready to be lit as part of a chain of signal fires stretching across the country to warn of a French landing. Local men enrolled in volunteer defence corps, drilling with muskets on the Heath at weekends, their red coats a vivid splash of colour against the gorse and heather.
The volunteer movement gained fresh momentum in the mid-Victorian period, when fears of French aggression under Napoleon III prompted the formation of the Rifle Volunteer Corps in 1859. Hampstead raised its own company, and the Heath became their regular training ground. These part-time soldiers — clerks, merchants, and professional men who traded their frock coats for uniforms on Saturday afternoons — practised musketry on improvised ranges and executed drills that owed more to enthusiasm than military precision. The movement was thoroughly middle-class, entirely in keeping with Hampstead's social character, and it established a tradition of local military service that would be drawn upon in far more desperate circumstances in the century to come.
The Hampstead volunteers left their mark on the village in various ways. The drill hall built for their use on Heath Street became a community landmark, hosting not only military exercises but also concerts, lectures, and social gatherings. Several of the grand houses along the eastern edge of the Heath were home to officers of the volunteer corps, men who combined successful careers in the City with a weekend commitment to national defence. Their memorials can still be found in St John's Church, Downshire Hill, where brass plaques record the names of Hampstead men who served in the volunteer forces across three generations.
The First World War and the Zeppelin Raids
The First World War transformed Hampstead from a genteel literary suburb into a community at war. Within weeks of the declaration of hostilities in August 1914, hundreds of local men had enlisted, many of them joining the London Regiment or the Artists Rifles, the latter unit having long-standing connections to the artistic community of St John's Wood and Hampstead. The Heath was commandeered for military training, its meadows churned by marching feet, and several large houses were requisitioned as officers' billets or convalescent homes for wounded soldiers returning from France.
But it was from the air that the war came most directly to Hampstead. The Zeppelin raids of 1915 and 1916 brought the horror of aerial bombardment to London for the first time, and while the airships' navigation was imprecise, their presence over north London caused widespread alarm. On the night of 8 September 1915, a Zeppelin designated L-13 crossed over the northern suburbs, and its bombs fell on areas within a few miles of the Heath. The explosions were clearly audible in Hampstead, and the sight of the great silver airship caught in the beams of searchlights became a defining memory for a generation of local residents. Anti-aircraft guns were positioned on the Heath's high ground, their crews scanning the night sky for the distinctive cigar-shaped silhouettes. The sound of their firing — a sharp, percussive crack quite different from the distant thud of the bombs — added to the din that shattered the village's peacetime tranquillity.
The war memorial on the corner of Church Row records the names of Hampstead men who fell in the conflict, a list that runs to several hundred names and encompasses every social class. Officers from the grand houses of Fitzjohn's Avenue are commemorated alongside working men from the cottages of Flask Walk and the lodging houses of Kilburn. The sheer length of the roll of honour is a stark reminder that even a community as privileged as Hampstead was not spared the terrible human cost of the Great War. By the Armistice of November 1918, Hampstead had lost a generation of its young men, and the scars of that loss would shape the village's character for decades to come.
The Second World War: Bombs, Shelters, and the Home Guard
If the First World War had introduced Hampstead to modern warfare, the Second plunged it into the conflict's very heart. The Blitz, which began in earnest on 7 September 1940, brought sustained aerial bombardment to London on a scale that would have been unimaginable to the Zeppelin-watchers of 1915. Hampstead, elevated and exposed, was hit repeatedly. High-explosive bombs and incendiary devices rained down on the village, destroying homes, shops, and churches that had stood for centuries. The damage was concentrated in several areas: the streets around South End Green took heavy punishment, as did Belsize Park, where entire terraces were reduced to rubble in single raids.
The Hampstead Home Guard — immortalised in popular imagination by Dad's Army but in reality a far more serious undertaking — patrolled the Heath nightly during the Blitz and throughout the war. Local men too old or otherwise ineligible for regular military service manned observation posts, checked blackout compliance, and trained for the invasion that, until late 1941 at least, seemed entirely possible. The Home Guard units stationed on the Heath were responsible for a network of defensive positions, including sandbagged emplacements at key road junctions and improvised roadblocks designed to slow any parachute assault on north London. Their commander was a retired colonel who lived in Well Walk and who brought a sometimes comical insistence on military protocol to what was essentially a force of middle-aged shopkeepers, retired schoolmasters, and teenage boys.
The deep-level shelter beneath Belsize Park tube station, built between 1940 and 1942, was one of the most significant military installations in the area. Capable of sheltering up to eight thousand people, it was part of a network of eight such shelters constructed beneath London Underground stations. But Hampstead's civilian population also sought refuge in more improvised shelters: the cellars of pubs, the crypts of churches, and the tunnels of the Northern Line itself. The crypt of St John's Church became an unofficial shelter during heavy raids, its thick walls and vaulted ceiling offering a reassuring sense of protection that the Anderson shelters in back gardens could not match.
Anti-aircraft batteries were positioned on the Heath throughout the war, their crews enduring freezing nights in sandbagged emplacements as they waited for the drone of incoming bombers. The batteries were part of London's Inner Artillery Zone, a ring of guns designed to put up a barrage through which enemy aircraft would have to fly. The noise was tremendous — the Heath's residents recall the guns as being more frightening than the bombs themselves — and the spent shell casings that rained down on surrounding streets were a constant hazard. Children collected shrapnel fragments as souvenirs, a grim hobby that speaks to the strange normalisation of danger that characterised life in wartime London.
SOE, Secret Operations, and the Espionage Community
Hampstead's role in the Second World War extended far beyond conventional military operations. The village and its surroundings played a significant part in the secret war, the covert operations conducted by the Special Operations Executive (SOE) and other intelligence agencies. SOE, established by Churchill in 1940 with the instruction to "set Europe ablaze," maintained several safe houses and training facilities in the north London suburbs, and Hampstead's large houses, many of them vacated by their owners during the Blitz, proved ideal for the purpose.
The precise locations of SOE's Hampstead operations remain partially classified even today, but enough has emerged from declassified files and the memoirs of former agents to sketch a picture of clandestine activity conducted in some of the village's most respectable streets. Agents destined for occupied France were briefed in drawing rooms where, just a few years earlier, literary hostesses had presided over afternoon tea. Radio operators practised their Morse code in attic rooms with blackout curtains drawn, their sets tuned to frequencies that connected them to resistance networks across the Channel. The quiet, residential character of Hampstead — its tree-lined streets, its air of bookish respectability — made it an unlikely but effective cover for operations that were anything but respectable.
The intelligence community's presence in NW3 was not limited to SOE. MI5, the domestic security service, maintained surveillance operations in the area throughout the war, monitoring the large émigré community that had settled in Hampstead and Belsize Park during the 1930s. Many of these refugees were entirely innocent — academics, artists, and professionals fleeing Nazi persecution — but the security services were acutely aware that enemy agents could hide among them. The Isokon Building on Lawn Road, a modernist block of flats that had attracted a cosmopolitan community of artists and intellectuals, was of particular interest to MI5, and for good reason: it had been home to several individuals who would later be exposed as Soviet agents.
The wartime intelligence infrastructure left a lasting legacy in Hampstead. The networks of contacts, the culture of secrecy, and the institutional knowledge accumulated during the conflict formed the foundation for Britain's post-war intelligence apparatus. Many of the men and women who had run SOE operations from Hampstead drawing rooms went on to careers in MI6 and GCHQ, carrying with them the habits of discretion and compartmentalisation that they had learned in the village's wartime safe houses. In this sense, Hampstead's contribution to the secret war did not end in 1945 but continued, quietly and invisibly, through the decades of the Cold War that followed.
Cold War Surveillance in NW3
The Cold War brought a different kind of military tension to Hampstead, one characterised not by bombs and barrage balloons but by surveillance, suspicion, and the quiet paranoia of espionage. The village's intellectual community — its writers, academics, and artists — included individuals whose political sympathies made them persons of interest to the security services. Left-wing politics had a long history in Hampstead, dating back to the socialist circles of the 1930s, and MI5 watched the area with an attention that belied its reputation as a haven of bourgeois liberalism.
The most notorious case of Cold War espionage connected to Hampstead centred on the Isokon Building and its pre-war residents. Arnold Deutsch, the Soviet intelligence officer who recruited the Cambridge Five — Kim Philby, Donald Maclean, Guy Burgess, Anthony Blunt, and John Cairncross — had lived at the Isokon in the 1930s, using its cosmopolitan atmosphere as cover for his recruitment activities. The building's architect, Wells Coates, had designed it as a vision of modern communal living, but its open-plan social spaces and transient population also made it an ideal environment for clandestine meetings and the cultivation of potential agents.
MI5's surveillance of Hampstead's intellectual circles continued well into the 1960s and beyond. Files released under the thirty-year rule reveal that the security services monitored the activities of various NW3 residents suspected of communist sympathies, tracking their movements, intercepting their mail, and in some cases placing listening devices in their homes. The targets ranged from prominent public figures — writers, broadcasters, and university professors — to more obscure individuals whose only offence was membership of organisations that the security services deemed suspicious. The Campaign for Nuclear Disarmament, which drew strong support from Hampstead's liberal intelligentsia, was a particular focus of MI5 attention, and its meetings in local halls and churches were routinely observed by plainclothes officers.
The irony of Cold War Hampstead was that the village's very qualities — its tolerance, its intellectualism, its cosmopolitan openness — were precisely what made it both attractive to those with radical political views and suspicious to those tasked with monitoring them. The security services and the watched community inhabited the same streets, drank in the same pubs, and browsed the same bookshops. It was a peculiarly English form of surveillance, conducted with a minimum of drama and a maximum of paperwork, and it left scars that were invisible but real. When the files were eventually opened, some of those who discovered they had been watched for decades expressed not anger but a weary recognition that their suspicions about being followed had been justified all along.
The Belsize Park Deep-Level Shelter and Its Afterlife
Of all the military installations associated with Hampstead, none is more remarkable — or more enigmatic — than the deep-level shelter beneath Belsize Park tube station. Built between 1940 and 1942 as part of a crash programme to provide bomb-proof accommodation for London's civilian population, the shelter is a feat of engineering that remains largely hidden from public view. It consists of two parallel tunnels, each over a thousand feet long, bored through the London clay at a depth of approximately one hundred feet below street level. The tunnels are lined with cast-iron segments and divided into upper and lower decks, creating a subterranean complex capable of accommodating up to eight thousand people.
The shelter's wartime history is well documented. It was opened to the public during the heaviest phase of the Blitz, providing a degree of protection that the shallow tube stations, where thousands of Londoners had taken to sleeping on the platforms, could not match. But the Belsize Park shelter also served a more exalted purpose. General Dwight D. Eisenhower, Supreme Commander of the Allied Expeditionary Force, used the shelter as a temporary headquarters during the planning of the D-Day invasion in 1944. The security of the deep tunnels, proof against any bomb then in existence, made them ideal for the most sensitive military planning, and Eisenhower's presence at Belsize Park is a reminder of the area's significance in the broader narrative of the Second World War.
After the war, the shelter was put to various uses that reflected the pragmatic spirit of post-war Britain. For a period it served as a government document storage facility, its constant temperature and humidity making it well suited to the preservation of paper records. Later, parts of the shelter were converted into a hostel, providing temporary accommodation in a city where housing was desperately short. The hostel operated for several years before the shelter was finally closed to regular use, though it was retained as a potential emergency facility throughout the Cold War, its tunnels periodically inspected and maintained against the possibility that they might once again be needed.
Today, the Belsize Park deep-level shelter is closed to the public and owned by Transport for London. Its entrances, marked by distinctive white-tiled surface buildings on Haverstock Hill, are the only visible evidence of the vast complex below. Proposals to open the shelter for tours or to convert it to commercial use surface periodically, but the engineering challenges and costs involved have so far prevented any such scheme from proceeding. The shelter remains one of Hampstead's most fascinating hidden spaces — a monument to wartime ingenuity and civilian resilience, buried deep beneath the feet of shoppers and commuters who pass above it every day without knowing it is there.
Echoes of Conflict in the Modern Landscape
The military and espionage history of Hampstead has left traces throughout the modern landscape, though many of them are easy to miss. The earthwork remains of Civil War fortifications can still be detected by those who know where to look, subtle undulations in the Heath's terrain that speak to a time when this open ground was a defensive perimeter rather than a recreational space. The sites of anti-aircraft batteries are marked by nothing more than slightly flattened areas of ground, the sandbagged emplacements long since removed and the grass grown back over the scars. In the streets of Belsize Park, the occasional gap in a Victorian terrace — filled now by a post-war block of flats — marks the spot where a bomb fell, erasing in a single night a building that had stood for a century.
The heritage of espionage is even harder to detect, which is perhaps appropriate for a history defined by secrecy. The Isokon Building still stands on Lawn Road, restored to something approaching its original appearance and once again functioning as residential flats. A small gallery in the building tells part of its espionage story, but the full tale — of agents recruited and secrets betrayed, of idealism perverted and loyalties divided — is too complex and too morally ambiguous to be captured in a museum display. The safe houses used by SOE have reverted to private homes, their wartime secrets locked away in classified files or lost to the memories of agents long since dead.
For those who work on Hampstead's historic buildings — renovating, restoring, and adapting them for modern life — this military and espionage heritage adds an additional layer of meaning to structures that are already rich in history. A Georgian townhouse that served as an SOE briefing centre carries a significance that extends beyond its architectural merits. A Victorian villa that was watched by MI5 surveillance teams holds stories that its current owners may never fully know. And the deep-level shelter beneath Belsize Park, invisible but immense, is a reminder that Hampstead's history is not confined to what can be seen above ground but extends deep into the clay and chalk beneath, where the tunnels of wartime still run silent and dark.
The village on the hill has always been shaped by forces larger than itself — political, military, ideological — and its buildings bear the marks of those forces in ways both visible and hidden. To understand Hampstead fully is to recognise that its story is not only one of literary salons and artistic bohemia but also of soldiers and spies, of bombs and bunkers, of secrets kept and secrets betrayed. It is a history that runs as deep as the shelters beneath Belsize Park, and it is woven into the very fabric of the place.
*Published in the Hampstead Renovations Heritage Collection — exploring the architecture, history, and stories of London's most remarkable neighbourhoods.*