The trout were photographed making giant leaps out of their pond into a fresh water  feed pipe a meter above the pond’s surface level.

They then fought against the current for 30ft to the mouth of the eight inch wide pipe in a tributary of the River Itchen near Alresford, Hants.

David Riley, owner of Hampshire Trout Farms, said he would be extremely surprised if many fish were making it through.

David Bassett, of the British Trout Association, said: "They will be thinking that water falling from the pipe is a waterfall leading upstream. Then they will follow their natural life cycle to get upstream."