A Norfolk river’s oxygen rate has been improved after around 100 fish were found dead.

Environment Agency workers have been trying to oxygenate the River Thet, near Thetford, to raise the levels after the hot weather caused it to fall to just 11pc.

Workers pump hydrogen peroxide into the water which reacts and gives off oxygen.

A spokesman for the Environment Agency said: “The oxygen levels have been improving with it rising to 50pc.

“We have not received anymore reports of fish in distress but as the weather changes this may be brief.

“We will continue to monitor the situation to see if any further issues arise.”

On Twitter the Great Ouse and Fenland Fisheries Team posted: “Tracking the source is difficult on an event like this.

“Oxygen levels this morning are between 40-70pc which is great news.”

To report an incident call the Environment Agency on 0800 807060