William Wickham PC PC (Ire) was a British spymaster and a director of internal security services during the French Revolutionary Wars. He was credited with disrupting radical conspiracies in England but, appointed Chief Secretary for Ireland, failed in 1803 to anticipate a republican insurrection in Dublin. He ended his career in government service in 1804, resigning his post in Ireland where, privately, he denounced government policy as "unjust" and "oppressive".

The Chief Secretary for Ireland was a key political office in the British administration in Ireland. Nominally subordinate to the Lord Lieutenant, and officially the "Chief Secretary to the Lord Lieutenant", from the early 19th century until the end of British rule he was effectively the government minister with responsibility for governing Ireland, roughly equivalent to the role of a Secretary of State, such as the similar role of Secretary of State for Scotland. Usually it was the Chief Secretary, rather than the Lord Lieutenant, who sat in the British Cabinet. The Chief Secretary was ex officio President of the Local Government Board for Ireland from its creation in 1872.