Trent Park House of Secrets review – the bugged stately home where German prisoners blabbed their secrets

History happened here. I mean, history happens everywhere. But serious, important, world-shaping history happened at Trent Park.

Built on the grounds of Enfield Chase, an expanse of Hertfordshire countryside used as hunting grounds by royalty, this country house has lived many lives. It was a Georgian retreat, a Victorian mansion, a post-Edwardian sanctuary, and then, during the second world war, it became a place of secrets. Afterwards, it became a university campus, before falling into dereliction. Now, it has been revived, and its hidden stories brought into the light.

The house was built after George III leased some land to his favourite doctor, Sir Richard Jebb, in the 1770s. It ended up in the hands of the Bevan banking family, who expanded and remodelled it, before the Sassoon family acquired it and did the same. Mega-socialite Philip Sassoon spent the equivalent of millions turning it into his dream country house in the 1920s – a suburban party palace frequented by the likes of Churchill and Wallis Simpson.

The house has been refurbished now, and is largely as Sassoon would’ve left it: pastel walls, floral curtains, countless deep, plush sofas for guests to lounge in. Flanking a huge bookcase in the library are portraits of Sassoon and his sister Sibyl by John Singer Sargent. They’re gorgeous paintings. Philip is intense, quiet, aloof. Sibyl is dark, elegant, sombre.

But it’s what is between the portraits that matters. Give that bookcase a shove and – hey presto! – a secret entrance down into the basement.

Of all of Trent Park’s transformations, this is its greatest: from aristo bolthole to audacious experiment in spycraft. After Sassoon died in 1939, the house was nabbed by the government and used as a prisoner of war camp for high-ranking German generals. Here, in these palatial surroundings, the prisoners were given time and space to pass the war in comfort, to kick back and let loose. But every inch of the house was bugged, even the rose bushes in the garden, every conversation recorded down in the basement, and listened to largely by German-speaking Jewish refugees. The prisoners felt at ease, so they spilled their secrets, and every word was recorded and transcribed.

The listeners got some pretty big intel, too. Information was fed to the Enigma code-breaking team over in Bletchley. General Ludwig Crüwell let slip to a fellow high-ranking officer about German ballistics, and the allies got the jump on the V2 rocket. Someone else blabbed about how German planes communicated with a system of transmitted beams, and the British kiboshed that too.

The basement has been faithfully recreated here: a mannequin sits at his station, headphones on, pen poised. The captain’s bed is neatly made, the housekeeper’s cellar is stocked with tea, herbs, wine and German books. It smells of damp, the wool blankets are rough and itchy, the sheets starched stiff. This was a place of resistance, of subterfuge, a place where the Germans could be lulled into a false sense of security and taken for all they had.

It wasn’t all good. Listeners heard conversations about German atrocities, but authorities did nothing with the information. They didn’t even submit the intelligence to the Nuremberg trials in the 1950s, worried their secret tech would be exposed.

Good or bad, it’s all lovingly recreated here, filled with neatly presented information and era-appropriate trinkets and decoration, though it’s a shame there aren’t more original artworks dotted throughout the house instead of copies.

The museum largely concentrates on the house’s role in the war, mainly because it’s interesting, and sets it apart from every other gaudy National Trust-style mansion in this country (though it is still definitely one of those). But it’s the clashing layers of history built into the house’s very foundations – caked into its paint and wallpaper – that make it feel special. In its transformation from Georgian to Victorian to mock-Georgian to war-time austerity and postwar dereliction, the house becomes a portrait of England’s changing fortunes and tastes, the way wealth has ebbed and flowed, the impact of immigration in shaping the country, and the way war can tear everything apart. That’s what is amazing about places like this, they’re not just grand houses, or follies of the rich brought back to life, they’re containers of history, and Trent Park sure saw its fair share of that.