Many of the worst attacks on mainland Britain in the past 30 years have been related to the conflict in Northern Ireland. Among them:
February 1974: Coach carrying soldiers and families in northern England is bombed by the Irish Republican Army (IRA). Twelve people killed, 14 hurt.
October-November 1974: Wave of IRA bombs in British pubs kills 28 people and wounds more than 200. Several people are convicted but cleared almost two decades later.
July 1982: Two IRA bomb attacks on soldiers in London's royal parks kill 11 people and wound 50.
December 1983: IRA Bomb at London's Harrods department store kills six.
October 1984: Prime Minister Margaret Thatcher's Cabinet narrowly escapes IRA bomb which kills five people at hotel in resort of Brighton during the Conservative Party's annual conference.
September 1989: Bomb at Royal Marines Music School in Deal, southeast England, kills 11 and wounds 22.
February 1991: IRA fires mortar bomb at Prime Minister John Major's London office. No one is injured.
April 1992: Car bomb outside Baltic Exchange in London's financial district kills three people and injures 91.
March 1993: Bombs in two litter bins in Warrington, northern England, kill two boys aged three and 12.
April 1993: IRA truck bomb devastates Bishopsgate area of London's financial district, killing one and injuring 44.
February 1996: Two people die when IRA detonates large bomb in London's Docklands area.
March 2001: A powerful car bomb explodes outside the BBC's London headquarters.
Police say the Real IRA, a republican splinter group opposed to the IRA's ceasefire, were behind the blast. One man injured.
July 2005: A number of people are killed in a series of explosions on London's transport system, causing chaos in the British capital. Several blasts hit the underground network and police there were several explosions on buses in the city.