“One of the duties of a sexton consisted of ‘tapping’ coffins, ‘so as to facilitate the escape of gases which would otherwise detonate from their confinement’.5 On occasion, the build-up of corpse gas was so intense that coffins actually exploded. In the 1800s, fires beneath St Clement Dane’s and Wren’s Church of St James’s in Jermyn Street destroyed many bodies and burned for days.”