Boris Johnson meets Whaley Bridge residents near collapse fears reservoir dam

Boris Johnson has visited residents and emergency crews in a Derbyshire town which has seen hundreds evacuated due to fears a nearby reservoir dam could collapse.

Water levels at the Toddbrook Reservoir have been reduced by half a metre but the damage to the 180-year-old structure remains at a “critical level”.

Residents of Whaley Bridge are being temporarily allowed to return home to collect essentials due to “a substantial threat to life” if the dam wall – which the Prime Minister described as “dodgy but stable” – fails.

An RAF Chinook and around 150 firefighters using high-volume pumps appear to have partly stabilised the “unprecedented, fast-moving emergency situation” caused by heavy rain.

Meeting locals at the Chapel-en-le-Frith High School, a few miles away from Whaley Bridge and currently being used as an evacuation centre, Mr Johnson called the damage “pretty scary”.

“The plan is to try and stop the dam breaking, clearly. And so a huge amount of effort is going into that,” he told a group of residents.

“The Chinook’s been over putting in the aggregate and putting in the sandbags to try and stop it bursting. They’re pumping out huge amounts of water.”

Mr Johnson, who arrived by helicopter, said he thought they had to get the level of the water down about eight metres, although there was some discussion with the surrounding officials about whether this was the exact figure.

He said: “They’ve got a long way to go. Whatever we do, we’ll make sure we rebuild it.”

During a multi-agency press conference, Assistant Chief Constable Kem Mehmet of Derbyshire Police asked residents to continue to heed police advice and stay away from the area.

“We will be putting plans in place for residents to return to their home to pick up very vital things they need along with their animal welfare,” he told reporters.

“This is very controlled, I must stress that, because this is still life at risk.”

Numbers returning will be restricted to one person per household, he said, and it was “difficult” to say when people would be allowed to return permanently.

Police have closed railway lines in the Whaley Bridge area over the risk of potential flooding.

Around 1,000 people were evacuated from the town but most found their own accommodation with family and friends, according to Derbyshire County Council.

The reservoir is on the north-west edge of the Peak District National Park and was built in 1831, according to experts, although the Environment Agency records it as being built in 1840-41.

According to a 2011 Environment Agency report on national dam incidents, Toddbrook “has a history of leakage”.