The Sussex Yeomanry is a yeomanry regiment of the British Army dating from 1794. It was initially formed when there was a threat of French invasion during the Napoleonic Wars. After being reformed in the Second Boer War, it served in the First World War and the Second World War, when it served in the East African Campaign and the Siege of Tobruk. The lineage is maintained by 1 (Sussex Yeomanry) Field Troop, 579 Field Squadron (EOD), part of 101 (London) Engineer Regiment (Explosive Ordnance Disposal) (Volunteers).