Confidential medical documents have been found abandoned in a derelict mental hospital.

Piles of patient records, x-rays and nurses’ notes have been abandoned in St Ebba’s Hospital in Epsom.

The old records were found by urban explorers – groups who photograph the inside of disused buildings as a hobby – in rooms formerly used by the hospital administration.

Several groups of explorers have visited St Ebba’s, a facility for patients with mental handicaps, and posted photographs in forums on the web.

One explorer, who did not want to be identified, said: "When you go into the hospital you can find records just thrown around everywhere. You can see the patients’ names and all the information about them. It’s all been abandoned."

Vice-president of the St Ebba’s Parents’ and Relatives’ Group Dr Maurice Brook said: "These are confidential records, they are not to be lying around like that."

Dr Brook’s son was once a patient of St Ebba’s Hospital. "When he moved out, he took his files with him," he said. "But it will be very upsetting for other former patients and their relatives to know their records are abandoned like that."

St Ebba’s Hospital is being closed gradually since the 90s, and the abandoned sites are now under the management of English Partnerships.

There is a plan to build a development on the site of St Ebba’s and of West Park – another derelict hospital – of 700 eco-houses, a hotel and a conference centre.

A English Partnerships spokeswoman said: "We always secure the sites and if people are hell-bent on breaking in then there is nothing we can do. When we have come across records on a site such as this we contact the NHS for their removal. In this case I believe there has been discussions with the NHS and the removal is happening."

A spokeswoman for Surrey and Borders Partnership NHS Trust, which is responsible for the management of St Ebba’s Hospital said: "The trust believes that all papers have been removed from the old hospital sites but, to make sure, we are currently checking disused buildings. We have to be sure that there is no risk to the staff who are being asked to do the checking and clearance work.

"If any papers are found they will be appropriately removed and securely stored."