D-Day secrets: Stately homes during the Second World War

RAF Medmenham recruits on the steps at Danesfield. Credit: Danesfield House

80 years ago, D-Day marked a turning point in the Second World War.  Far from the Normandy beaches, a number of stately homes played a pivotal – and top-secret – role in wartime operations

Words by Felicity Day

What happened on D-Day?

”D-Day has come,” a BBC newsreader told Britons early on 6 June 1944, Allied forces having launched the largest invasion in history across the Channel in Northern France. Involving 156,000 troops, 11,590 aircraft and almost 7,000 vessels, ‘Operation Overlord’ would mark the beginning of the end of the Second World War. But the invasion on that June day, 80 years ago, could not have happened had it not been for the work ongoing for months beforehand in a large, turreted house in the Chiltern Hills.


Danesfield House

Danesfield, built for a soap magnate in 1901, was home to RAF Medmenham, where over 1,700 men and women worked capturing and studying aerial reconnaissance photographs and producing intelligence reports – around 600,000 of the former and 1,500 of the latter every month in the run-up to D-Day, as they monitored the roads and railways around Normandy, and mocked-up models of the landing sites to brief the Overlord forces.

Using stereoscopes that presented offset images separately to their left and right eyes, giving the illusion of three-dimensional depth, Medmenham’s photographic interpreters were able to see an incredible level of detail in the images captured by the crews of camera-loaded Spitfires. By D-Day they had already made the Dambusters’ raid possible with intelligence on water levels and anti-aircraft defences in the area, and helped Bomber Command to track their hit-rate.

Without doubt, the D-Day landings would have been a considerably riskier undertaking without those toiling amid the Neo-Tudor splendour of Danesfield. And it was just one of countless British country houses to play a pivotal role in the defeat of Nazi Germany.   

Bletchley Park

The Library at Bletchley Park. Credit: Simon Broadhead.

Some, like Bletchley Park, have long since spilled their secrets. The subject of Hollywood films and hordes of books, the code-breaking work of its mathematical masterminds – who were intercepting, deciphering and translating German messages in as little as two-and-a-half hours by D-Day – has made the one-time country retreat of a Victorian financier a household name.

Hughenden Manor

The north front Hughenden. Credit: ©National Trust Images/Andrew Butler

Others have kept their secrets close. And few closer than Hughenden Manor in Buckinghamshire. The National Trust had owned and cared for Hughenden for near-on 60 years before they discovered, quite by chance, its wartime alias Hillside, and the indispensable work undertaken behind its great gothic doors. Only when a volunteer overheard a gentleman talking to his grandson was its past life as a top-secret map-making base revealed.

For four years a team of 150 beavered away inside the red-brick country residence of Victorian Prime Minister Benjamin Disraeli, hand-drawing and printing over 3,500 target maps for use by Bomber Command on their night-time raids. Chosen for their drawing skills, the Hillside staff wielded not weapons but paintbrushes, bending over workbenches in grand rooms that had once welcomed Queen Victoria, leaving only Disraeli’s study unused.


Beaulieu. Credit: Tony Watson / Alamy

The National Trust might not have known about Hillside, but Herr Hitler did, and it was not the only historic house with which the Nazis were well-acquainted. They knew all about the series of properties scattered across the 800-year-old Beaulieu estate, being used to train some of their most formidable adversaries, the agents of the Special Operations Executive.

Some 3,000 volunteers of at least 17 different nationalities passed through Beaulieu between 1941 and 1945, the so-called ‘Finishing School’ there preparing them for the day when they would parachute into occupied Europe and join up with resistance forces.  

An inspection of an American bomber aircraft at Beaulieu in 1942. Credit: public domain sourced / access rights from De Luan / Alamy

In an idyllic corner of Hampshire, they were taught the arts of subversion and sabotage – drilled, by day, in everything from forgery, burglary and safe-breaking to silent killing and the swift disposal of corpses, by instructors who, by night, dined with the family of Lord Montagu; still living in the estate’s Palace House, but utterly ignorant until VE Day of what and who was being taught on their ancestral acres.

Croome Court

Beaulieu’s agents-in-training would be embarking on one of the most dangerous forms of wartime service; the SOE expected to lose 50 percent of its recruits in the field. But there was perilous work ongoing in Britain, too – some at the stately Croome Court in Worcestershire.

The magnificent Neo-Palladian seat of the Earls of Coventry, remodelled by ‘Capability’ Brown in the 1750s, Croome was requisitioned in 1940, the year that the 10th Earl was killed in the retreat to Dunkirk. By 1942, its extensive parkland had become home to RAF Defford airfield, and a top-secret facility carrying out trials of radar and other pioneering electronic equipment.

It was the experimental nature of the work at Croome that made it hazardous – test flights trialling trailblazing equipment and techniques could push aircraft to their limits. On one particularly black day in 1942, a bomber carrying a new radar crash-landed, killing all 11 of the aircrew and engineers on board. But it was vital work: technology trialled on-site was instrumental in seeking and destroying German U-boats in the Battle of the Atlantic.  

Winston Churchill addressing a crowd at Blenheim Palace. Credit: Mary Evans Picture Library 2015

Blenheim Palace

Like Croome, Blenheim Palace was involved in testing military apparatus. On the Duke of Marlborough’s own Capability Brown-designed lake, British-made amphibious vehicles were secretly piloted in the run-up to D-Day; photos show the 11th Duke himself aboard. It is thought that the lake was also the site of testing for the enormous floating drums that eventually laid ‘PLUTO’ – the miles-long ‘pipeline under the ocean’ that supplied fuel to the Channel force.

Hush-hush as such tests were, Blenheim have yet to find proof of the latter, though they have long known what went on inside the Palace. MI5 moved into its spectacular state rooms in 1940, working on the database of persons posing a possible threat to national security.

Blenheim was used as a test site for military apparatus

Vanbrugh’s Baroque palace was a huge improvement on the spooks’ previous abode, Wormwood Scrubs prison. Possibly, Churchill pulled a few strings to secure them accommodation in his birthplace; it’s likely that he had a hand in Blenheim’s selection as a test site.

The famously indomitable leader did not always get his own way, however. Determined to go to sea on D-Day to witness the invasion unfold, he was forced to back down when King George VI threatened to accompany him. Instead, the pair monitored events from a hidden bunker – not in Downing Street or Whitehall, but in the grounds of yet another stately pile.

Bentley Priory

Bentley Priory was the HQ of RAF Fighter Command

Bentley Priory, perched atop a hill overlooking the London borough of Harrow, and formerly home to an ailing Queen Adelaide before becoming a Victorian hotel and a girls’ school, had been readied for wartime service in 1936, when it became RAF Fighter Command’s HQ. It was the nerve centre during 1940’s Battle of Britain, from where Air Chief Marshal Hugh Dowding masterminded the RAF’s critical victory over the Luftwaffe, staving off a German invasion of Britain.

On D-day, movements of vessels and aircraft – both Allied and enemy – were nimbly plotted on the table-top map in the operations room in its concrete bunker, overseen not only by the King and the Prime Minister, but the commander of the whole invasion, General Eisenhower.

General Eisenhower pictured at Bentley Priory in 1944. Credit: Bentley Priory Museum

Were it not for the Spitfires parked on the front lawn, you might never know that it had, like so many of its fellow stately homes, such an important wartime history. 80 years on, that deserves to change.

Visit these stately homes to find out the secrets for yourself:

Danesfield is now a country house hotel and spa, but it hosts monthly tours exploring its time as RAF Medmenham. danesfieldhouse.co.uk

Bletchley Park have faithfully recreated the rooms used for the vital code-breaking work that took place here and will be holding events to mark the D-Day anniversary. bletchleypark.org.uk   

Hughenden House holds a permanent exhibition celebrating the work of the secret map-makers of Hillside. nationaltrust.org.uk

Beaulieu is home to a dedicated SOE museum, with a new exhibition for 2024 exploring the lives of two especially remarkable agents. beaulieu.co.uk

Croome has an RAF Defford Museum, housed in the airfield’s former medical facility. nationaltrust.org.uk

Blenheim Palace has a permanent exhibition dedicated to Winston Churchill, who was born at the house. blenheimpalace.com

Bentley Priory is now a museum, commemorating both the courageous pilots Churchill labelled ‘the Few’, and ‘the Many’ who supported them on the ground. bentleypriorymuseum.org.uk

Read more from BRITAIN:

Secrets of D-Day: Bletchley Park codebreakers

Royal portraits: Photos at the palace

Elizabethan London: Royals and rogues