2000 MI6 attack  The 2000 MI6 attack was an attack on MI6's SIS Building headquarters in Vauxhall, Lambeth, London. 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. Although London had been the targets of terrorist attacks before 2000, it had not been subjected to a rocket launcher attack; this was the first time a RPG-22 rocket launcher was seen and used in Great Britain. It was initially thought the Real IRA acquired the launchers from the Provisional IRA's arsenal, but later confirmed it was brought from the former Yugoslavia. The "audacious" attack caused minimal damage due to the building's bullet-proof and bomb-proof structure, failing to penetrate the inner cladding. 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. London had been the target of a similar attack in 1991 when an IRA mortar shell was fired at 10 Downing Street and exploded during a cabinet meeting held by then Prime Minister John Major. Before the Real IRA's MI6 attack, Hammersmith Bridge was damaged by a small bomb blast in June 2000, resulting in the bridge requiring renovation. A further planting of a bomb occurred near Ealing Broadway station in July 2000. A by-election in the constituency of South Antrim was scheduled to be held the day after the attack. Democratic Unionist William McCrea was elected with 37.95% of the votes, defeating fellow candidates Ulster Unionist David Burnside, Donovan McClelland of the Social Democratic and Labour Party, Martin Meehan of Sinn Féin, David Ford of the Alliance Party of Northern Ireland and David Collins of the Natural Law Party. Three members of the RIRA went into an area of Spring Gardens and used a grassy knoll to fire their 2.8 kg RPG-22 missile about 300 metres away from the SIS Building. At 21:45 the grenade caused damage to a green plated glass window, yards below sensitive satellite equipment on the building's roof which was believed to be the main target.