Question: How many people were killed on the ground in the most deadly incident of terrorism in the United Kingdom ?

text: List of major crimes in the United Kingdom
Terrorism
Excludes incidents that happened during the Troubles in Northern Ireland . See also Attacks on the London Underground , List of terrorist incidents in Great Britain and List of terrorist incidents in London .
This is a list of major crimes in the United Kingdom that received significant media coverage or led to changes in legislation. Legally each deliberate and unlawful killing of a human being is murder; there are no crimes of assassination or serial killing as such, for example.
Date Name No . of Deaths Location Details
1867 The Clerkenwell explosion 12 Clerkenwell , London A bomb planted by Fenians at New Prison in Clerkenwell exploded , killing twelve passers-by and more than 120 injuries
1972 The 1972 Aldershot bombing 7 Aldershot , England A bomb attack by the Northern Ireland-based Official Irish Republican Army , the first of its kind on the mainland , targeted a British Army base in Aldershot . Seven civilian staff were killed
1973 The 1973 Old Bailey bombing 1 London , England The first attack in England by the Provisional IRA . Four car bombs were planted at significant targets in London including Scotland Yard & the Ministry of Defence . Two bombs were defused but two bombs exploded , the worst damage was caused by the bomb at the Old Bailey were over 200 people were injured & one man died of a heart attack . The attack caused outrage in England & got extensive media coverage
1973 The Bombings of King 's Cross and Euston stations - London , England Two 2 to 3 pounds ( 0.9 to 1.4 kg ) bombs at mainline stations injured 13 people and brought chaos to central London . The first explosion at King 's Cross station - which injured five people - occurred without any warning at 1224 BST , seconds after a witness saw a youth throw a bag into a booking hall . Fifty minutes later a second blast rocked a snack bar at Euston station , injuring a further eight people
1973 The 1973 Westminster bombing - London , England A bomb exploded in Thorney Street , which leads off Horseferry Road . The bomb was planted in a car which was known to have been stolen in London , and was parked outside Horseferry House , a building occupied by the Home Office , and opposite Thames House , which is mainly occupied by the Department of Trade and Industry . Both these buildings , and others nearby , were extensively damaged . At least 40 people were injured
1974 The M62 coach bombing 12 M62 motorway , West Riding of Yorkshire , England A bomb attack on a coach killed nine British Army soldiers and three civilians . The attack was carried out by the Provisional Irish Republican Army
1974 The 1974 Houses of Parliament bombing - London , England A bomb exploded at the Houses of Parliament in London , causing extensive damage and injuring 11 people
1974 The 1974 Tower of London bombing 1 London , England An explosion in the Tower of London left one person dead and 41 injured . This was the second bomb in London on this day . At 0430 BST there was an explosion at government buildings in Balham , South London . Nobody was injured in the morning blast but there was substantial damage to surrounding buildings
1974 The Guildford pub bombings 5 Guildford , England Two bombs at a pub in Guildford cause the deaths of four soldiers and a civilian . IRA terrorists were responsible
1974 The Brook 's Club bomb attack - Brook 's , St James 's Street , London A 5-pound ( 2.3 kg ) bomb exploded in the Brooks Club , London , injuring three members of staff
1974 The Harrow School bombing - Harrow , England The Harrow School bombing happened on 24 October 1974 , when the Provisional IRA 's Balcombe Street Gang bombed Peterborough Cottage , a three-storey former caretaker 's house in the grounds of Harrow School . A warning was given and there were no deaths or injuries
1974 The Birmingham pub bombings 21 Birmingham , England 21 people were killed when bombs went off in two pubs in central Birmingham . Six men were wrongly convicted and spent 16 years in prison before being released in 1991
1974 The 1974 London pillar box bombings - London , England Provisional IRA exploded bombs inside pillar boxes in various places around London , injuring 40 people
1974 The Oxford Street bombing - London , England The IRA carried out a bomb attack on Selfridge 's department store in Oxford Street , London . A time bomb had been placed in a car which was then parked outside the store . Three telephone warnings were given and the area was evacuated . The explosion was later estimated to have caused £1.5 million worth of damage
1982 The Hyde Park and Regent 's Park bombings 11 London , England Bomb attacks against a military ceremony in London killed eleven soldiers
1983 The Harrods bombing 6 London , England Six people were killed when a bomb detonated near the Harrods department store in London
1984 The 1984 Heathrow Airport bombing - Heathrow Airport , England On 20 April 1984 , a bomb exploded in the baggage area of Terminal 2 at Heathrow Airport . The bomb exploded at 7:55 pm , as 60 people were inside the baggage area . The blast injured 22 , one seriously . The Angry Brigade , an anarchist group , claimed responsibility for the bombing . British officials dismissed the claim , and instead pointed their fingers at Libyan-related Arab groups . coming just three days after the murder of Yvonne Fletcher
1984 The Brighton hotel bombing 5 Brighton , England A bomb attack targeting members of the government killed five people . The then Prime Minister , Margaret Thatcher , narrowly escaped injury
1988 The Lockerbie Disaster 270 Lockerbie , Dumfries and Galloway , Scotland In one of the worst terrorist attacks in the UK , London-New York commercial flight Pan Am Flight 103 crashed near Lockerbie , Scotland as the result of a bomb having been planted in the forward cargo hold . A joint investigation by the Dumfries and Galloway Constabulary and the ( U.S. ) Federal Bureau of Investigation linked the bombing to Abdelbaset al-Megrahi , a Libyan intelligence officer and the head of security for Libyan Arab Airlines . He was jailed for life in January 2001 with a recommended minimum of 20 years ( later increased to 27 years ) , but was released on compassionate grounds due to terminal cancer in August 2009 , and returned to his native Libya , where he died in 2012
1989 The Deal barracks bombing 11 Deal , England Eleven soldiers died after the IRA bombed a military facility in Deal