These pictures show firefighters battling a blaze which raged for 24 hours at the historic Cane Hill asylum on Saturday.

The fire began in the basement of a locally listed building on the derelict site at 8.41am and ripped through three floors with visible flames shooting through roof.

No one is thought to have been injured but up to 80 per cent smoke and fire damage was caused to the administration block of the Victorian asylum, which was opened in 1883 and treated mentally ill patients for 115 years before it was shut down in 1992 and marked for demolition.

The fire brigade is investigating the cause of the fire, although at this stage, it is not being treated as suspicious at the moment.

A firefighter from the Green Watch, on duty at Purley fire station, helped battle the blaze with up to 40 of his colleagues.

He said: “There were eight fire engines on the scene and between 30 and 40 fire fighters. The fire was quite big, fighting fires can be physically exhausting. We usually get relief after three or four hours, but because we do not have the man power at the moment, or the fire engines, relief was only every five to six hours.”

Liam Craik-Horan, 19, who has a keen historic interest in the site and has taken a number of photographs of the site.

He said: “I went there by chance on Saturday, I was nearby and I wanted to see what was left of the place. To my horror it was on fire. It was about 4pm and the fire was nearly out but still flaming quite a lot. I was told the fire started in the basement.”

The hospital is being demolished by developers English Partnerships, which is drawing up development plans it hopes to start consulting residents on in May 2011.

The administration building is only locally listed so developers do not have a statutory duty to maintain it.

A spokeswoman from English Partnerships said: “We are waiting for the damage report from London Fire Brigade before we decide what to do with the building.”

The hospital looked after soldiers who lost their sanity during the two world wars. Twenty-six WWI heroes, who died at the hospital, were buried in unmarked graves at the Cane Hill cemetery and forgotten about for 91 years until they were uncovered by local historian Adrian Falks in 2009. The graves have now been moved to Mitcham Road Cemetery.