PM Boris Johnson describes Peak District dam at risk of collapse as 'pretty scary'

Water levels at the Toddbrook Reservoir in Whaley Bridge have been reduced by half a metre since Thursday – when heavy rainfall caused cracks to first appear in the dam wall - but the damage to the 180-year-old structure remains at a critical level.

Hundreds of evacuated residents spent another night away from their homes on Friday and police warned it could be several days before they are allowed to return.

Meanwhile, the rail line between Sheffield and Manchester is blocked and out of use until next Tuesday morning.

An RAF Chinook and around 150 firefighters using high-volume pumps – including one from Sheffield – appear to have partly stabilised the reservoir's spillway, with further pumps brought in by officials last night.

Prime Minister Boris Johnson, who arrived by helicopter last night, promised that the damaged reservoir would have a "major rebuild" as he met locals at nearby Chapel-en-le-Frith High School, which is being used as an evacuation centre.

Describing the damage to the dam as "pretty scary", he said: "The plan is to try and stop the dam breaking, clearly. And so a huge amount of effort is going into that."

The Prime Minister 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 added: "I was talking to one of the villagers from Whaley Bridge who said that he remembered something like this happening 50 years ago.

"We've had an exceptional weather event, we must make sure that this dam can cope with it in the future.

"That will mean a major rebuild, clearly."

Those evacuated from their homes were allowed to return briefly on Friday evening to pick up any vital items or pets.

The operation allowed just one person from each household to return for a maximum of 15 minutes.

Derbyshire Police said that any residents who re-entered Whaley Bridge would be doing so at their own risk and that the threat to life remained high.

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

As efforts to stabilise the dam continue today, the Met Office has issued a yellow weather warning for much of northern England and the Midlands on Sunday, which includes the area around the reservoir.

It warns there could be damage and disruption from floodwater and lightning strike.