All 259 passengers and crew were killed, as were 11 residents of Lockerbie.

An investigation concluded the eplosion was caused by a bomb. But despite strong suspicions of Libyan involvement, so far no one has been brought to trial.

The Lockerbie case has been closely linked with a French investigation into UTA flight 772 from Brazzaville to Paris, which exploded over the Ténéré desert in Niger the following year killing 171 people.

• The explosions

  21 December 1988: Pan Am flight 103 from Frankfurt to New York, via London, explodes over the Scottish town of Lockerbie. All 259 passengers and crew were killed, as were 11 residents of Lockerbie.

  19 September 1989: UTA flight 772 from Brazzaville to Paris explodes over the Ténéré desert in Niger killing 171 people.

• The investigation

  30 October 1991: A French examining magistrate issues arrest warrants against six Libyan officials for their alleged involvement in the UTA bombing.

  14 November 1991: A three-year investigation concludes with the Lord Advocate, Scotland's chief law officer, obtaining a warrant for the arrest of two Libyans, Abdel Baset Ali Mohamed al-Megrahi and Al-Amin Khalifa Fhimah. The charges against them are of conspiracy, murder, and contravention of the Aviation Security Act of 1982. An indictment is also issued in the US containing similar accusations.

• The Lockerbie accused

  
  

  Abdel Baset al-Megrahi

  Abdel Baset al-Megrahi: 46-years-old, he is alleged to have been a senior officer of the Libyan Intelligence Services. Head of Libyan Arab Airlines security in Malta in December 1988, alleged to have bought clothes in a Maltese store that were contained in the suitcase bomb on board flight 103.

  
  

  al-Amin Khalifa Fhimah

  Al-Amin Khalifa Fhimah: 42-years-old, also alleged to to belong to Libyan inteligence and to have been station officer of Libyan Arab Airlines in Malta.

• The trial trail

  27 November 1991: The British, US and French Governments issue a joint statement calling on the Libyan Government to surrender all the accused for trial.

  8 December 1991: Libya says it will try the men itself.

  21 January 1992: UN Security Council Resolution 731 orders Libya to surrender the Lockerbies suspects.

  23 March 1992: Libya offers to hand suspects over to the Arab League.

  31 March 1992: UN Security Concil Resolution 748 gives Libyans 15 days to hand over the suspects or face a worldwide ban on air travel and arms sales and the closure of Libyan Arab Airline offices.

  15 April 1992: UN embargo takes effect.

  30 April 1992: Libyan leader Colonel Gadaffi says he will not hand the men over but they are free to surrender.

  11 November 1993: UN Security Council Resolution 883 repeats the earlier demands and threatens to tighten sanctions.

  1 December 1993: Sanctions imposed, including the freezing of Libyan assets in foreign banks and an embargo on oil industry-related equipment.

  29 January 1994: Libya maintains its refusal to hand over the two suspects.

  24 January 1995: British MPs call for a new inquiry after the publication of US intelligence service documents suggesting that Iran and not Libya was behind the bombing.

  2 July 1998: The UN Security Council extends sanctions for a further four months.

  21 July 1998: The British and US Governments indicate that a trial in a third country under Scottish law may be acceptable.