A project to protect river animals by eradicating mink has seen the East of England become the only place in Britain where water vole populations are increasing, according to a wildlife trust.

Until recently, the River Colne in Essex had struggled with water vole numbers because of mink, an invasive non-native species introduced to the UK in the 1960s.

But a programme to boost numbers by partners including Essex Wildlife Trust (EWT) and Waterlife Recovery Trust has seen an “absolute explosion of wildlife and particularly the water voles”, said the EWT’s Darren Tansley.