A forgotten WWII air raid shelter which protected hundreds of people from German bombs has been discovered in a park.

The shelter, which has space for up to 1,000 people, was discovered after a hole appeared in the ground in Carshalton Park.

It was uncovered by a council worker in just his second week in the council parks department.

Tom Webb said: “When we first got a call saying that a hole had appeared I thought that it would just be a missing manhole cover, but as soon as I got down to the park I realised that it was much more.

"Once it was safely cordoned off, I went straight back to the office to find out what was down there.

"Using information from satellite images and old council minutes, we discovered that an air raid shelter capable of holding 1,000 people was built under the park, possibly to help people in the nearby cottage hospital safe.”

It is believed that the shelter consisted of a rectangle of four corridors, approximately five feet across, which would have housed people sitting on wooden benches. Local historian John Phillips said: “Sutton is one of London’s greenest boroughs so it’s likely that air raid shelters were built in most of its parks- but they were filled in after the war and although there are records on some, many have been forgotten about.”

Carshalton was hit a number of times by German Luftwaffe bombers during the war and also suffered a number of V1 rocket strikes. Preliminary investigations suggest the rediscovered shelter is in good condition and officials now plan to excavate it further.

The area has been cordoned off ahead of excavation work being carried out. Councillor Graham Tope, executive member for community safety, leisure and libraries, said: “It’s potentially a significant find which could shed some fresh light on wartime Britain.

“We understand the Government of the day ordered it to be built for people who couldn't afford an Anderson shelter in their garden or who didn't have a garden. “We would love to hear from residents who know more about it - or who even took shelter in it during a raid.” Photographs and information about the shelter could be featured in a future exhibition at the nearby Honeywood Museum, which is due to reopen later this year after a major refurbishment.

In 2010, a similar air raid shelter was discovered when a five metre hole appeared in Sutton Green.

Anyone with information can contact Maura Collyer on 0208 770 5070 or by emailing parks.serviceenquiries@sutton.gov.uk