The management of a heritage site accused of neglecting historical artefacts has said it needs more money to refurbish buildings.

Last week a concerned volunteer, who asked to remain anonymous for fear of the sack, showed the Guardian the storage area at Royal Gunpowder Mills in Waltham Abbey.

Previous exhibition pieces such as rocket parts, Second World War radar equipment, Victorian fire engines and other unique items were stored in leaking buildings, were unprotected and kept in poor conditions.

Lance Bourne, general manager of the Royal Gunpowder Mills, said: "One of the biggest problems is that many buildings are in need of attention and we can only store artefacts in the buildings we own.

"We don’t have the funds to repair them but we do our level best to keep artefacts dry and in the best condition we can."

The current owners are in talks to lease the historical site, which has been in operation for 300 years and specialised in the production of explosives.

Mr Bourne added: "We are seeking investment to improve all our buildings in the future."