Christopher Somerville explains how he set out to find the wildest places in the British Isles

CATCOTT HEATH, Somerset

Maps: OS Explorers 140, 141; Landranger 182 - (OS ref 407412)
Location: west of Glastonbury

Catcott Heath, in the flatlands north of the Polden Hills, is a classic example of a preserved Somerset Levels wetland - juicy and oozing with water, full of wildflowers, dragonflies, butterflies and birdlife. Marsh orchids, marsh and meadow thistles, meadowsweet and ragged robin thrive. The southern edge is a waterlogged woodland, where silver birch and willow shoot up tall, fungi sprout on decaying boughs, and alders suck up moisture from ground that is partly wet black peat, partly a rich midden of rotting boughs and logs.

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THAMES ESTUARY FORTS, Kent

Location: off Whitstable
Viewing trips: www.bobleroi.co.uk

Storm-battered, salt-bitten, rusty and decrepit, the Second World War forts out in the Thames Estuary resemble robots from Star Wars or The War of the Worlds more than they do any conventional fortification. Red Sands and Shivering Sands are clusters of four-legged towers; Knock John and Rough Tower are both composed of a pair of mighty cylindrical legs joined by a rectangular platform. Rough Tower is now the “Independent Principality of Sealand”, with its own royal family, flag, national anthem, stamps, passports and currency. This is a wild place like no other.

TETNEY MARSHES, Lincolnshire

Maps: OS Explorer 282, Landranger 113 - (OS ref 355031)
Location: south of Cleethorpes

The RSPB's Tetney Marshes Reserve in its remote coastal landscape comprises 1,620 ha (4,000 acres) of the sort of land that nobody else wants: barren miles of tidal sand, mudflats, sombre swaths of saltmarsh and big, bare fields over which skylarks pour out song without pausing as they climb their aerial ladders. In autumn the marshes grow a handsome coat of sea lavender, brilliant purple-blue in strong sunlight. But in winter this is a bleak place under huge skies clamorous with packs of pink-footed and brent geese.

CWM IDWAL, Snowdonia, North Wales

Maps: OS Explorer 17, Landranger 115
Location: Off A5, west of Capel Curig (OS ref 649604)

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