Never forget that the British political and media elite endorsed slavery. It took radical campaigners to end it

A visitor to the National Portrait Gallery looks at the painting The Anti-Slavery Society Convention, 1840, by Benjamin Robert Haydon. Photograph: Sarah Lee/The Guardian

Two hundred years ago tomorrow, a few dozen old friends and comrades gathered in a tavern on Poultry, the short street in central London. That tavern, the King’s Head, was known for its “unsophisticated wines and honest measures”. It acquired its name in 1660, when the restored Charles Stuart rode past and bowed to the tavern’s mistress. Who promptly fainted.

Now, there is no trace of the place at all. When I last looked for it, I found only the premises of a pharmacist, a tailor and a travel agency. Yet on 31 January 1823, a date for which there is no monument and not even a blue plaque, the King’s Head tavern played host to the inaugural meeting of the Anti-Slavery Society.