File:2024-09-04 London Stone - 06.jpg

English: London Stone is a historic landmark housed at 111 Cannon Street in the City of London. It is an irregular block of oolitic limestone measuring 53 × 43 × 30 cm (21 × 17 × 12"), the remnant of a once much larger object that had stood for many centuries on the south side of the street.

The name "London Stone" was first recorded around the year 1100. The date and original purpose of the Stone are unknown, although it is possibly of Roman origin. There has been interest and speculation about it since the medieval period, but modern claims that it was formerly an object of veneration, or has some occult significance, are unsubstantiated. The present London Stone is only the upper portion of a once much larger object. A study in the 1960s indicated that the stone is Clipsham limestone, a good-quality stone from Rutland transported to London for building purposes in both the Roman and medieval periods. In 1940 St Swithin's church was burnt out by bombing in the Blitz. However, the outer walls remained standing for many years, with London Stone still in its place in the south wall. In 1962 the remains of the church were demolished, and replaced by an office building, 111 Cannon Street. London Stone was placed without ceremony in a specially constructed Portland stone alcove, glazed and with an iron grille, in the new building. Inside the building it was protected by a glass case. The stone and its surround, including the iron grille, were designated a Grade II* listed structure on 5 June 1972. In the early 21st century the office building was scheduled for redevelopment, and in October 2011 the then landowners proposed to move the stone to a new location further to the west. Objections were raised by, among others, the Victorian Society and English Heritage, and the proposal was rejected by the City of London Corporation.

Until February 2016 the ground floor of the building was occupied by a branch of WHSmith newsagents. Inside the shop London Stone in its glass case was hidden behind a magazine rack and not usually accessible. In March 2016, planning permission was granted to allow the building to be demolished and replaced by a new one. The Stone was put on temporary display at the Museum of London while the building works were carried out. It was returned to Cannon Street in October 2018. The new premises publicly display London Stone on a plinth, within a Portland stone casing loosely inspired by its 19th-century predecessor, and behind glass.