Sir William Patrick Byrne KCVO CB PC (Ire) (12 February 1859 – 11 June 1935) was a senior member of the British Civil Service.
He proceeded to study law at London University, gaining his degree in 1881 and was called to the bar at Gray's Inn.
In 1908, Byrne was elected a Bencher and served as Principal Clerk in the Home Office 1896–1908, he then served as Assistant Undersecretary of State for the Home Department from 1908 to 1914, and was involved in dealing with the suffragettes protest movement.
[3] Between 1913 and 1921, Byrne served as Chairman of the Board of Control for Lunacy and Mental Deficiency.
[5] From 1915 to 1916, Byrne served two terms as Treasurer of Gray's Inn[6] and as Undersecretary to the Lord Lieutenant of Ireland.