Many accurate 1921 census transcriptions have already been added to the pub history site, including London, and parts of Middlesex. If you can contribute to the site, send me some details to Kevan, along with some description of the specific property.
Clerkenwell pub history index
It only seems to appear in 1841 directory. *
A listing of historical London public houses, Taverns, Inns, Beer Houses and Hotels in Clerkenwell, London.
Residents at this address.
* Provided By Ewan