John Brock died on 5 November 1720 aged 43 and is buried at St James's Church, Clerkenwell, London.

In 1825 the factory was located in a residential area in Baker's Row (now Vallance Road), Whitechapel, London: it was destroyed when a boy who was ramming gunpowder into a firework accidentally created a spark which ignited it, and threw it aside as he ran out in fright.

Fifty pounds of gunpowder and a large amount of saltpetre exploded immediately, blowing the roof off, setting fire to the building, and smashing every pane of glass in most of the adjoining streets.

[5] Henry Brock died on 4 October 1901 at age 53, and was buried at Holy Trinity Church, Leverstock Green.

[6] During the Second World War the company made the famous "target markers"[fn 2] used by the RAF's Pathfinder Force (PFF).