Under cover of darkness, a nocturnal creature emerges from a crate and takes its first tentative steps into a new life in the wild.
"It is just essentially God's work. We're undoing the damage of hundreds of years ago and bringing back these extraordinary animals," claimed Ben, who spoke to the BBC on the condition of anonymity.
He is part of an underground network where members risk arrest, jail and hefty fines by carrying out covert and unlicensed releases of beavers.
It is an offence to release beavers into the wild without a licence and a spokeswoman for the National Farmers Union (NFU) said it was "irresponsible" and "really worrying".
There is now a legal route in the UK for the species to be reintroduced. Despite this and the risks of acting without licences, activists whose names have been changed were unrepentant and said they were taking action themselves because the legal option was "too bureaucratic".
