The Protestant Association of London has the support of leading Calvinist religious figures among  including Rowland Hill, Erasmus Middleton, and John Rippon.

Lord George Gordon had become its President in 1779, in an effort to force the repeal of the Papists Act.

An articulate propagandist, though eccentric, Gordon had inflamed the mob with fears of Papism and a return to absolute monarchical rule.

He implied that Catholics in the military will, given a chance, join forces with their co-religionists on the Continent and attack Britain.

He enjoys popularity in Scotland where he takes part in a successful campaign to prevent the same legislation from being introduced into Scots law, although the Act continues in force in England and Wales and in Ireland.