On 10 January 1985 an explosion destroyed the central section of a three-storey block of luxury flats in South London, killing eight of the residents. Preliminary investigations indicated a gas leak as a probable cause.

It was found that the explosion was caused by gas leaking into the building from a crack in the gas main, a 150mm (6 inch) diameter cast iron pipe buried at the rear of the building, which carried gas at low pressure. The crack was primarily due to loading on the pipe caused by differential settlement. The loading could not be evenly distributed along the pipe, as it was held rigidly near the point of failure by the concrete encasement of a drain, which acted as a fulcrum.

Report: https://www.icheme.org/media/13699/the-putney-explosion.pdf

Image Credit: HSE