According to the Environment Agency (EA), most fish were likely to have swum away from the noise and disturbance caused by the 23 high-volume pumps that were deployed to drain out the reservoir's water.

"If you speak to fisherman they will say don't thump when you're walking along the bank," said Mark Scott, the agency's area director.

He said the sound of all the pumps "thumping away" would have sent a clear signal to the fish to keep away.

In addition, the pumps used by the fire service had strainers on them which, according to Derbyshire chief fire officer Terry McDermott, would have stopped the fish from getting sucked up.

"The fire service pumps float on the surface, not affecting the fish," he said.

However, naturalist Martin James said: "It's quite possible there would be lots of small fish - or fry - from this year's spawning which would easily be sucked into the pipes."