THESE pictures reveal how a primary school was once the site for a network of tunnels dating back to the Second World War.

Builders working at St Mary’s Prittlewell CofE Primary School, in Boston Avenue, Southend, discovered the tunnels as they carried out excavations at the site to extend the school building to accommodate more reception pupils.

The tunnels are 6ft wide, 9ft deep, and run as long as 40ft beyond where the new classroom is being constructed.

They are made from reinforced concrete.

Headteacher Francis Neil said: “They run in a zigzag shape that would have helped to protect those that would have been in the shelter if they were unlucky enough to be caught in a blast.

The idea is the corners help to slow the movement of air and debris down.

“It’s quite something to find a war shelter in your playground. They’re in incredible condition, which is amazing when you think how old they are.

“They are made with quite beautiful screeded concrete and are of high-quality workmanship.

“It’s a wonderful thing for the children as well because they can now link it in with their history class and learning about the war.”

The shelter has not been dug out and is believed to be under the playground.

The tunnels will be filled with concrete this week for the work to continue, but plenty of photographs and video footage have been taken to document the find.

Ken Crowe from Southend Central Museum, who has also seen tunnels at Southend High School for Boys, said: “Every school with a playing field had these tunnels. If the siren sounded during the war, the children and teachers would all go down the tunnels to the shelter.

“There’s a complex set of tunnels and most people wouldn’t even know they were there.”

Mrs Neil added: “The discovery of the tunnels will not delay the opening of the new reception class area in September. It will be wonderful when it is ready with the children having their own outdoor area like a classroom.

“Everything is back on schedule.”