Operation Flavius (also referred to as the Gibraltar killings) was a military operation in which three members of the Provisional Irish Republican Army (IRA) were shot dead by the British Special Air Service (SAS) in Gibraltar on 6 March 1988. The trio were believed to be planning a car bomb attack on British military personnel in Gibraltar. They were shot dead while leaving the territory, having parked a car. All three were found to be unarmed, and no bomb was discovered in the car, leading to accusations that the British government had conspired to murder them. An inquest in Gibraltar ruled that the authorities had acted lawfully but the European Court of Human Rights held that, although there had been no conspiracy, the planning and control of the operation was so flawed as to make the use of lethal force almost inevitable. The deaths were the first in a chain of violent events in a fourteen-day period. On 16 March, the funeral of the three IRA members was attacked, leaving three mourners dead. At the funeral of one, two British soldiers were murdered after driving into the procession in error.

In late 1987, British authorities became aware of an IRA plan to detonate a bomb outside the governor's residence in Gibraltar. On the day of the shootings, known IRA member Seán Savage was seen parking a car near the assembly area for a military parade; fellow members Daniel McCann and Mairéad Farrell were seen crossing the border shortly afterwards. As SAS personnel moved to intercept the three, Savage split from McCann and Farrell and ran south. Two soldiers pursued Savage while two others approached McCann and Farrell. The soldiers reported seeing the IRA members make threatening movements when challenged, so the soldiers shot them multiple times. All three were found to be unarmed, and Savage's car did not contain a bomb, though a second car, containing explosives, was later found in Spain. Two months after the shootings, the documentary "Death on the Rock" was broadcast on British television. Using reconstructions and eyewitness accounts, it presented the possibility that the three IRA members had been unlawfully killed.

The inquest into the deaths began in September 1988. The authorities stated that the IRA team had been tracked to Málaga, where they were lost by the Spanish police, and that the three did not re-emerge until Savage was seen parking his car in Gibraltar. The soldiers testified that they believed the suspected bombers had been reaching for weapons or a remote detonator. Several eyewitnesses recalled seeing the three shot without warning, with their hands up, or while they were on the ground. One witness, who told "Death on the Rock" he saw a soldier fire at Savage repeatedly while he was on the ground, retracted his statement at the inquest, prompting an inquiry into the programme which largely vindicated it. The inquest returned a verdict of lawful killing. Dissatisfied, the families took the case to the European Court of Human Rights. Delivering its judgement in 1995, the court found that the operation had been in violation of Article 2 of the European Convention on Human Rights as the authorities' failure to arrest the suspects at the border, combined with the information given to the soldiers, rendered the use of lethal force almost inevitable. The decision is cited as a landmark case in the use of force by the state.

The Provisional Irish Republican Army (IRA) aimed to establish a united Ireland and end the British administration of Northern Ireland through the use of force. The organisation was the result of a 1969 split in the Irish Republican Army; the other group, the Official IRA, ceased paramilitary activity in the 1970s. The IRA killed civilians, members of the armed forces, police, judiciary and prison service, including off-duty and retired members, and bombed businesses and military targets in both Northern Ireland and England, with the aim of making Northern Ireland ungovernable. Daniel McCann, Seán Savage, and Mairéad Farrell were, according to the journalist Brendan O'Brien, "three of the IRA's most senior activists". Savage was an explosives expert and McCann was "a high-ranking intelligence operative"; both McCann and Farrell had previously served prison sentences for offences relating to explosives.

The Special Air Service is part of the United Kingdom's special forces. The SAS was first assigned to operations in Northern Ireland in the early stages of the British Army's deployment there, but were confined to South Armagh. More widespread deployment of the SAS began in 1976, when D Squadron was committed. The SAS specialised in covert, intelligence-based operations against the IRA, using more aggressive tactics than regular army and police units.

From late 1987, the British authorities were aware that the IRA was planning an attack in Gibraltar. The intelligence appeared to be confirmed in November 1987, when several known IRA members were detected travelling from Belfast to Spain under false identities. MI5—the British Security Service—and the Spanish authorities became aware that an IRA active service unit (ASU) was operating from the Costa del Sol and the members of the unit were placed under surveillance. After a known IRA member was sighted at the changing of the guard ceremony at the Convent (the governor's residence) in Gibraltar, the authorities suspected that the IRA was planning to attack the British soldiers with a car bomb as they assembled for the ceremony in a nearby car park. In an attempt to confirm the IRA's intended target, the government of Gibraltar suspended the ceremony in December 1987, citing a need to repaint the guardhouse. They believed their suspicions were confirmed when the IRA member re-appeared at the ceremony in February 1988.

In the following weeks, Savage, McCann, and Farrell travelled to Málaga (90 miles [140 kilometres] along the coast from Gibraltar), where they each rented a car. Their activities were monitored and by early March, the British authorities were convinced that an IRA attack was imminent; a team from the SAS was despatched to the territory, apparently with the personal approval of the British prime minister, Margaret Thatcher. Before the operation, the SAS practised arrest techniques, while the Gibraltar authorities searched for a suitable place to hold the would-be bombers after their arrest. The plan was that the SAS would assist the Gibraltar Police in arresting the IRA members—identified by MI5 officers who had been in Gibraltar for several weeks—if they were seen parking a car in Gibraltar and then attempting to leave the territory.

According to the official account of the operation, Savage entered Gibraltar undetected at 12:45 (CET; UTC+1) on 6 March 1988 in a white Renault 5. An MI5 officer recognised him and he was followed, but he was not positively identified for almost an hour and a half, during which time he parked the vehicle in the car park used as the assembly area for the changing of the guard. At 14:30, McCann and Farrell were observed crossing the frontier from Spain and were also followed. They met Savage in the car park at around 14:50 and a few minutes later the three began walking through the town. After the three left the car park, "Soldier G", a bomb-disposal officer, examined Savage's car and reported that the vehicle should be treated as a possible car bomb. Soldier G's suspicion was conveyed as certainty to four SAS troopers, Soldiers "A", "B", "C", and "D". Gibraltar Police Commissioner Joseph Canepa handed control of the operation to "Soldier F", the senior SAS officer, at 15:40. Two minutes later, the SAS moved to intercept the IRA operatives as they walked north on Winston Churchill Avenue towards the Spanish border. As the soldiers approached, the suspects appeared to realise that they were being followed. Savage split from the group and began heading south, brushing against "Soldier A" as he did so; "A" and "B" stayed with McCann and Farrell and Soldiers "C" and "D" followed Savage.