Police officers in Whaley Bridge are preventing residents from returning home in a bid to 'preserve lives'.
Residents were permitted to return to their homes for just 15 minutes on Friday evening and Saturday to collect vital medication and pets - but this has now been stopped after the Met Office extended a thunderstorm warning increasing the threat to lives.
More than a thousands residents were evacuated from the High Peak town on Thursday after a week of torrential showers caused a damage to part of the Toddbrook Reservoir, the Manchester Evening News reports.
Authorities who managed the controlled operation to permit people briefly back into their homes to collect essential items signed people in and out as they drove through a roadblock.
Anyone who decided to travel home was told they did so "at their own risk".
But now Derbyshire Police have issued an urgent update saying the decision has been taken to stop residents from returning home at all - however briefly.
The Met Office today extended a yellow weather warning for thunderstorms across the region which subsequently raises the risk of the dam's collapse.
The police force announced the news in a series of tweets.
The Derbyshire Police wrote: "Urgent update: Whaley Bridge. The decision has today, Sunday 4 August, been taken to stop allowing evacuated residents back to their homes in Whaley Bridge. This is effective immediately.
"The original decision to allow urgent visits home was to allow residents to collect pets and necessary medication and other vital items. Residents and businesses were supported by officers throughout Friday evening and Saturday to enter their addresses for a controlled period.
"The attention of officers and other responders has to be on the preservation of life and, while there was an urgent need over the past 24 hours to allow residents back into the area, our first duty is to protect the lives of the public and emergency services.
"Further heavy rain is forecast from around 1pm today (Sunday 4 August) which also has the potential to increase the flow of water entering the Toddbrook Reservoir.
"The multi-agency response to this incident continues today and emergency services and partners are working around the clock to ensure the safety of the town and surrounding area.
"The multi-agency response to this incident continues today and emergency services and partners are working around the clock to ensure the safety of the town and surrounding area."
Boris Johnson visited Whaley Bridge on Friday where he vowed to residents to properly house residents if the reservoir dam collapses.
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 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.
"They've got a long way to go. Whatever we do, we'll make sure we rebuild it."
The helpline number for evacuated residents is 01629 533190.
There is also an e-mail address for anyone wishing to donate items or services - emergency.planning@derbyshire.gov.uk
