The privately owned home in Wimbledon Park Road was undergoing renovation work when a recently altered two storey rear extension came crashing down last Wednesday.

Fearing the imminent collapse of the rest of the three-story house, police and fire fighters cordoned off the street and called in the council’s building control duty officer and the town hall’s emergency response team.

The team are on call 24 hours a day to respond to any situation in Wandsworth which may involve a dangerous building or structure.

Principal building control officer Robert Foulger said: “We got a call from the police at about 6pm telling us that the rear extension had collapsed and that they were concerned that the whole building might fall down.

“We were able to get to the address with our equipment pretty quickly, which was fortunate because the building was in a pretty precarious state. It was in a very dangerous condition and could have gone at any time.

“We had to work against the clock, in dangerous conditions, to get some emergency supports in to prop up the upper floors and the rest of the brickwork, which took us about four hours, but fortunately we managed to catch it in time.

“We are now investigating what happened to the extension and why it collapsed. It was definitely very lucky that the builders who were working there had left shortly before the collapse and that no passers-by were injured.”

Where necessary the danger will be removed immediately by the council's own specialist contractors under the close supervision of an experienced senior building control officer who will ensure that the work is carried out in the most suitable way.