Combe was present in the House of Commons when the then Prime Minister, Spencer Perceval, was assassinated in the lobby on 11 May 1812. He chaired a makeshift court convened the same day composed of MPs who were, like himself, also magistrates in order to begin committal proceedings against the murderer, John Bellingham, take witness statements and order messengers to search Bellingham's lodgings. Bellingham was ultimately hanged.