Salmon must leap upstream in rivers before they can spawn, and Environment Agency expert Jim Finnegan said this is what the fish was pictured trying to do at Borrowash Weir, on the Derwent.

He said: 'We have been down there and seen salmon trying to leap over the weir.

'But the ultimate objective is to see them spawning or breeding in the Derwent, and there's no evidence of that yet.

'We will need to build these fish passes.'

Chris Wood, from Derbyshire Wildlife Trust, said: 'It's very encouraging news to see salmon attempting to cross these barriers.

'It's what we want to see and it's a testament to the health of the river and the work of the Environment Agency.'