Hundreds of residents could be unable to return to their homes for 48 hours after an unexploded wartime device was found at a school.
A 300-metre exclusion zone was set up following the discovery at the Royal High School in Lansdown Road in Bath at 4.40pm on Thursday.
Contractors unearthed the 500lb Second World War shell from beneath the surface of the school’s playground, which had been in use until a few years ago, and an Explosive Ordnance Disposal (EOD) team was called to the site.
People living in up to 1,000 homes nearby were evacuated throughout the night and during the early hours of Friday morning.
Bath & North East Somerset Council posted images on Twitter showing volunteers erecting green blow-up beds at a reception centre.
Local schools could be affected by the incident and drivers have been asked to consider if it is “absolutely necessary” for them to travel into the city.
Chief Inspector Kevin Thatcher, of Avon and Somerset Police, said: “We recognise the disruption this incident has already caused to residents inside the exclusion zone and we’d like to thank them for their patience.
“Decisions to evacuate houses are never taken lightly but during these incidents public safety will always be our primary concern.
“We also appreciate the anxiety many in the local community may feel following the discovery of the device and the time required to remove it but we would urge people not to be alarmed.
“The EOD are working as quickly as they can to remove the device and we will provide regular updates on their progress.”
After the shell was discovered, at about 6pm, after studying pictures of the find, police were instructed to set up a cordon and evacuate those properties within it.
A number of those evacuated are now taking refuge in the Pavilion by Bath Recreation Ground.
The EOD team are currently building a barrier around the device using 250 tonnes of sand.
Once this is in place, they will remove the device with a police escort to a safe location away from the Bath area, where they will carry out a controlled explosion.
A police spokesman said: “Avon and Somerset Police are working closely with their partners at Bath & North East Somerset Council, South West Ambulance Service and Avon Fire and Rescue to look after those temporarily evacuated.
“Unfortunately, once outside the exclusion zone, residents are unable to re-enter while the incident is ongoing, which at this stage is believed may be up to 48 hours.
“Some residents inside the cordon have chosen to remain in their homes and they continue to be advised to move to a safe distance.
“Those who have remained inside the exclusion zone will be prevented from moving within 100m of the device for their own safety.”
Commuters are advised to expect significant disruption on the roads throughout Bath while diversions are in place and are asked to plan their journeys ahead.
A spokesman for Bath & North East Somerset Council said: “Schools close to the cordon may be affected and the advice is to consult the council website, Twitter feed, local radio stations, as well as look out for messages from the schools themselves.
“The Lansdown Park & Ride service will be closed today. Additional Park & Ride services will be running from the Newbridge site and the Odd Down site.”
Lansdown Road will be closed between Lansdown Lane and Julian Road, as well as roads immediately adjacent to Lansdown Road within the 300m exclusion zone.
“In order to minimise disruption and any knock-on effects, members of the public are advised to carefully consider if it is absolutely necessary for them to travel into Bath today or whether they can avoid making the journey – such as working from home or an alternative location, or visiting the city on a different day,” the council spokesman added.