William Clements served in the Royal Ulster Rifles and the Royal Irish Rangers, commanding the 1st Battalion. He was Defence and Military Attache at the British embassies in Beijing and Rangoon.
He has long had a fascination for fortifications and is the author of Towers of Strength, Defending the North; the Fortifications of Ulster 1795-1945, Martello Towers Worldwide (in print with Pen and Sword) and Billy Pitt Had Them Built, Napoleonic Towers in Ireland.
He has contributed articles to the journals of the Fortress Study group, the Military History Society of Ireland and the Society for Army Historical Research. In 2011 he was elected a Fellow of the Royal Historical Society.