A channel called The Great Deep partially separates the mainland from Thorney Island, part of the watery maze that is Chichester Harbour.
Owned by the MoD, the island played an important part in the Battle of Britain. Now a rather idyllic station for the Royal Artillery, walkers following the Sussex Border Path can gain access by pressing a button at barbed-wire-topped gates and enjoy a nine-mile circular stroll.
Surrounded by deserted white-sand and shingle beaches and with mudflats beyond, this peaceful island connects via a sandbank with Pilsey Island (no public access), a habitat for Brent geese, curlews, skylarks, egrets, shelduck and osprey.
See more of Secret Britain
Mynydd Carningli, Pembrokeshire: The ancient volcano in the shape of a reclining woman
The peak of this remote mountain in West Wales is the next spot to make our Secret Britain list.
Humphry Repton's 'secret country gem' at Endsleigh, one of the finest hotel gardens in Britain
Non Morris explores the historic 100-acre grounds of Endsleigh, Olga Polizzi’s alluring West Country hotel, designed by Humphry Repton in
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Five years, 10,400 miles and a boatload of stories: Mark Ashley-Miller on the Country Life PodcastMark Ashley-Miller, the man who sailed to every harbour in Britain and Ireland, joins the Country Life Podcast.
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Country Life 17 September 2025Country Life 17 September 2025 looks at the best homes for sale in the Cotswolds, indulges in country kitchens and examines Britain's Roman legacy.
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St Patrick’s Chapel ruins, Heysham: The mythical Lancashire ruins with a heavenly viewAnnunciata Elwes takes a look at St Patrick’s Chapel ruins, a Morecambe Bay landmark.
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Suisnish, Isle of Skye: The atmospheric ruins of a Clearance villageBeauty now reigns in a tragic spot where hundreds of villagers suffered during the Clearance
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Covehithe beach, Suffolk, where the cliffs crumble like cakeThe most eroded beach in Britain has a post-apocalyptic feel.
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Clydach Ironworks, Monmouthshire: Ruins in the gorge that inspired ShakespeareAn oasis of quiet now stands where the steam hammers thudded at this Welsh ironworks, in a river valley that may have moved Shakespeare to write A Midsummer Night’s Dream.
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Royston Cave, Hertfordshire: A mysterious site full of sacred energyOur Secret Britain series continues with a Hertofrdshire cave whose true nature remains unknown.
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John Bunting War Memorial Chapel, Scotch Corner: The painstaking transformation of rubble to War MemorialAnnunciata Elwes celebrates the effort that turned a derelict house into a memorial.
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The Garden of Cosmic Speculation: The surreal space where Lewis Carroll and Willy Wonka meet Capability BrownSurrealism, philosophy, nature and gardening come together at the Garden of Cosmic Speculation, as Annunciata Elwes explains.
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The Airman’s Grave, Ashdown Forest: A touching and little-known memorial to victims of war and fateA wartime tragedy in East Sussex's Ashdown Forest is among our Secret Britain picks, as chosen by Annunciata Elwes.
