An explosion in a Battersea housing block which injured four people and forced a mass evacuation of flats was caused by thieves, it has emerged.

The incident took place inside a privately owned flat in Dungeness House, York Road, shortly after 8pm on January 25 when a hot water tank blew up, demolishing two walls and shattering windows.

On Tuesday, the subsequent investigation revealed thieves had disabled one of the heating system’s vital safety features by snatching and then sealing off copper vent pipes that feed into the block’s water tank in the roof.

According to investigators, copper pipes are “an essential safety feature that allow excess water and steam to escape from the hot water cylinder if it should overheat”.

As well as stealing the copper piping, the thieves covered their tracks by capping the remaining pipework to prevent it from leaking and causing a flood - causing the water to overheat until the tank blew up. An inspection of other roof tanks on the estate uncovered similar thefts.

Wandsworth Council’s housing spokesman, Councillor Guy Senior, said: “We are very concerned at what we have found. Whoever did this is putting people’s lives at risk for the sake of a few pounds worth of scrap metal.

“Our advice to anyone who uses an immersion heater that starts emitting unusual sounds or noises is that they should switch it off immediately and contact the housing department’s emergency team who are able to respond 24 hours a day.

“We are now going to undertake an urgent check of all blocks to see if this theft is an isolated case or a more widespread problem.”

About 49 residents were led to safety from the block after the explosion by firefighters who were called at 8.19pm.

A man was taken to hospital by the London Ambulance Service (LAS). An LAS spokeswoman said the man was suffering back pain. She added a woman and three children were treated at the scene but did not require hospital treatment.

Three fire engines and a fire rescue unit from Battersea, Clapham and Wandsworth stations attended the incident, which was over by 9.04pm.

LAS sent two ambulance crews, a single responder unit, a duty officer and a hazardous area response team.

To contact the council call 020 8871 6000.

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