On Wednesday 20 September 2000, the Real Irish Republican Army (RIRA) carried out an attack on MI6's SIS Building headquarters in Vauxhall, Lambeth, London. A Russian-built RPG-22 anti-tank rocket, fired 300 metres (330 yards) away from MI6 headquarters, struck the building on the south side of the eighth floor, causing superficial damage. No fatalities or injuries were recorded. At the time of the attack, the constituency of South Antrim was preparing for a by-election to be held the following day; it was won by Democratic Unionist William McCrea, who defeated Ulster Unionist David Burnside.