Balcombe Street Siege The Balcombe Street Siege was an incident involving members of the Provisional Irish Republican Army ( IRA ) and the Metropolitan Police Service of London lasting from 6 to 12 December 1975 . The siege ended with the surrender of the four IRA volunteers and the release of their two hostages . The events were televised and watched by millions . Background . In 1974 and 1975 London was subjected to a 14 - month campaign by the Provisional IRA , including gun and bomb attacks . Some 40 bombs exploded in the capital , killing 35 people and injuring many more . In one incident the " Guinness Book of Records " co - founder and conservative political activist Ross McWhirter was assassinated ; he had offered a £50 , 000 reward to anyone willing to inform the security forces of IRA activity . The four members of what became known as the ' Balcombe Street gang ' – Martin O ' Connell , Edward Butler , Harry Duggan and Hugh Doherty – were part of a six - man IRA Active Service Unit ( ASU ) that also included Brendan Dowd and Liam Quinn . Quinn had recently shot dead police constable Stephen Tibble in London after fleeing from police officers . The flat he was seen fleeing from was discovered to be a bomb factory used by the unit . The Balcombe Street siege started after a chase through London , as the Metropolitan Police pursued Hugh Doherty , Joe O ' Connell , Eddie Butler and Harry Duggan through the streets after they had fired gunshots through the window of Scotts Restaurant in Mount Street , Mayfair . They had thrown a bomb through the restaurant window a few weeks before on 12 November 1975 , killing one person and injuring 15 others . The Metropolitan Police Bomb Squad had detected a pattern of behaviour in the ASU , determining that they had a habit of attacking again some of the sites they had previously visited . In a scheme devised by a young Detective Sergeant , the Met flooded the streets of London with unarmed plain - clothes officers on the lookout for the ASU . The four IRA men were spotted as they slowed to a halt outside Scotts and fired from their stolen car . Inspector John Purnell and Sergeant Phil McVeigh , on duty as part of the dragnet operation , picked up the radio call from the team in Mount Street as the stolen Cortina approached their position . With no means of transport readily available , the two unarmed officers flagged down a taxi cab and tailed the men for several miles through London , until the IRA men abandoned their vehicle . Purnell and McVeigh , unarmed , continued the pursuit on foot despite handgun fire from the gang . Other officers joined the chase , with the four IRA men running into a block of council flat s in Balcombe Street , adjacent to Marylebone rail station , triggering the six - day stand - off . Purnell was subsequently awarded the George Medal for his bravery . Several other police officers were also decorated . The siege . The four men ended up in a flat at 22b Balcombe Street in Marylebone , taking its two residents , John and Sheila Matthews , hostage . The men declared that they were members of the IRA and demanded a plane to fly both them and their hostages to Republic of Ireland . Scotland Yard refused , creating a six - day standoff between the men and the police . Peter Imbert , later Commissioner of the Metropolitan Police , was the chief police negotiator . The men surrendered after several days of intense negotiations between Metropolitan Police Bomb squad officers Detective Superintendent Peter Imbert and Detective Chief Superintendent Jim Nevill , and the gang ' s leader Joe O ’ Connell , who went by the name of " Tom " . The other members of the gang were named " Mick " and " Paddy " , thereby avoiding revealing to the negotiators precisely how many of them were in the living room of the flat . The resolution of the siege was a result of the combined psychological pressure exerted on the gang by Imbert and the deprivation tactics used on the four men . The officers also used carefully crafted misinformation , through the BBC radio news — the police knew the gang had a radio — to further destabilise the gang into surrender Trial . The four were found guilty at their Old Bailey trial in 1977 of seven murders , conspiring to cause explosions , and falsely imprisoning John and Sheila Matthews during the siege . O ’ Connell , Butler and Duggan each received twelve life sentences , and Doherty eleven . Each of the men was later given a whole life tariff , the only IRA prisoners to receive this tariff . During their trial they instructed their lawyers to " draw attention to the fact that four totally innocent people were serving massive sentences " for three bombings in Woolwich and Guildford . Despite claiming to the police that they were responsible , they were never charged with these offences and the Guildford Four and Maguire Seven remained in prison for fifteen more years , until it was determined that their convictions were unsafe . Release . After serving 23 years in UK jails the four men were transferred to the high security wing of Portlaoise Prison , 50 miles ( 80 km ) west of Dublin in early 1998 . They were presented by Gerry Adams to the 1998 Sinn Féin Ard Fheis as ‘ our Nelson Mandela s ’ , and were released together with Brendan Dowd and Liam Quinn in 1999 as part of the Good Friday Agreement .