Ben Cottam puts on full waterproofs to cross the causeway to Sunderland Point, in search of the grave of a black slave. There are 43 tidal islands around the UK, accessible just briefly each day along beguiling paths. Across the series, five writers journey across a favourite causeway to islands of refuge, pilgrimage, magic and glamour. Wheels spin wildly and Ben peers anxiously through mud-sprayed windscreen as he tries to drive to Sunderland. There is no real boundary between land and sea, the coastline as fluid as the tide. The danger signs escalate and he remembers tales of insidious rising waters, drilled into him as a child by coastguards from Morecambe Bay. He treks to what is uncomfortably called Sambo’s grave, the resting place of young black slave. Abandoned there by a sea captain in the 18th century, Ben wonders how his own family might have treated him and is heartened to find fresh tributes marking a lost life. Producer: Sarah Bowen

W N Herbert

W N Herbert

Claire McGowan enters the freezing waters off Burgh Island, connected at low tide to the mainland by a short sandy causeway. There are 43 tidal islands around the UK, accessible just briefly each day along beguiling and perilous paths. Across the series, five writers walk their favourite causeway to islands of refuge, pilgrimage, magic and glamour. Claire grew up with the mythology of the giant Finn McCool flinging rocks at a rival in Scotland and building the Giant’s Causeway. Arriving at Burgh Island, she steps into tranquil 1920s glamour, to sip Agatha Christie inspired cocktails in the Art Deco hotel bar. In this time capsule, Claire explores our relationship with Golden Age Crime and her own past; as the tide retreats, past relationships disappear with the waves and time simultaneously changes and stays still. Producer: Sarah Bowen

There are 43 tidal islands around the UK, accessible just briefly each day, along beguiling and perilous paths. As the tide retreats, five writers walk their favourite causeway to islands of refuge, pilgrimage, magic and glamour. Today, Evie Wyld boards the ferry at Lymington pier and retraces a path well-travelled with her family during school holidays - across the Freshwater Causeway on the Isle of Wight. Her route takes her past ghost benches, a graveyard, World War Two pill boxes on a journey through grief, memory and what survives the tide. Across the series: Claire McGowan sees time change as she enters the freezing waters off Burgh Island and sips cocktails in the art deco hotel bar. Ben Cottam almost gets stuck in the mud as he searches for the grave of a black slave and questions his family’s past at Sunderland Point. WN Herbert follows in the footsteps of pilgrims to Lindisfarne and reflects on the causeway leading to a meditational space. And between kite surfers and dog walkers, Patrick Gale is suspended between two worlds as he follows the S shaped causeway, shaped by relentless tides and currents to St Michael’s Mount. As sea levels rise and the sands shift, causeways are in flux. The essayists draw us down onto the sands, revealing what these liminal routes mean to both them and the cultural history of the UK. Producer: Mohini Patel