Countryfile – Northey Island opens Anita Rani’s four-part coastal road trip along England’s east coast, and it begins with one of the boldest conservation ideas broadcast this year: three retired Thames barges deliberately sunk into the Blackwater Estuary to build a brand-new refuge for threatened shore birds. Northey Island sits near Maldon on the Essex coast, a 110-hectare landscape of salt marsh and wetland that shelters curlew, black-tailed godwit, teal and thousands of dark-bellied brent geese every winter. Yet rising seas are squeezing this habitat hard, and without intervention almost all of its salt marsh could vanish within a century.