The school was originally established by the Honourable and Loyal Society of Antient Britons, a London-based Welsh society, as a charitable institution to assist impoverished Welsh children in London. In the later 18th century it was also supported by the Honourable Society of Cymmrodorion, another London Welsh society. The school opened informally in 1716 in a house in Sheer Lane, London, and was more formally instituted in 1718. In 1719 it moved into one of the buildings of Ailesbury Chapel, Clerkenwell, the former chapel of the medieval Clerkenwell Priory, but at this date in use as a Presbyterian meeting-house. The chapel was reconstructed as an Anglican parish church in 1721–3, when the school appears to have moved to nearby Jerusalem Passage. The numbers of pupils fluctuated through this period, though there were at times up to 50 boys. . In 1738 the school moved into a new purpose-built home on Clerkenwell Green. The construction of this building, designed by James Steer, was funded by subscriptions. The building survives, and is now the Marx Memorial Library. The first girls were admitted to the school in 1758. In 1768, a decision was taken to admit a small number of residential pupils: the first were six girls. Thomas Pennant's British Zoology was published "under the auspices of the Cymmrodorion Society", and "sold for the benefit of the British Charity-School on Clerkenwell Green". Pennant in fact lost heavily on the publication, and so the school derived no direct benefit from it. Independently of this work, however, he did give the school a donation of £100. Conditions at Clerkenwell Green became increasingly cramped, and in 1772 the school moved into a new building in Gray's Inn Lane. The school now became predominantly residential.
Ashford
In 1857 the school moved out of London to a new site at Ashford, Middlesex. It began to have difficulty attracting charitable pupils, and in 1882 was reconstituted to admit a higher proportion of fee-paying pupils, and as a school exclusively for girls. It now became known as the Welsh Girls' School. During World War II the school was evacuated to the Powis Castle estate in Montgomeryshire, but returned to its Ashford site in 1946. In the post-war period its connections with Wales became more tenuous, and in 1967 the name was changed to St David's School. The school closed in 2009 because of falling numbers caused by economic recession. In 2010, the Ashford buildings were taken over by St James Independent Schools and opened as St James SeniorBoys' School.
