The ‘London Stone’ is a mysterious block of limestone that currently sits, ignored by passers-by, in an alcove in the wall of a building opposite Cannon Street Station. Already a subject of speculation in the 16th century, subsequently identified in turn as a Roman milestone, as a Druid monument, as the ‘Stone of Brutus’ and as ‘London’s original fetish stone’, it is now considered by some to play an essential role in the ‘sacred geometry’ of London. How have such diverse opinions as to its purpose arisen? – and can we truly identify its date and its original function?

If you take a late lunch on Wednesday you can pop along to the Guildhall Library and find out more in a lecture by John Clarke, a Senior Curator of London, from 2-3pm. Entrance is free, but you’ll need to book in advance.