Key dates in the three decades since the Lockerbie bombing.
December 21: Pan Am flight 103 explodes over the Scottish town of Lockerbie, killing 270 people – 259 on board and 11 on the ground.
January 31: Following a trial at Camp Zeist in the Netherlands, Libyan intelligence officer Abdelbaset al-Megrahi is found guilty of mass murder and jailed for life.
August 19: Libya accepts blame for the Lockerbie bombing and agrees to compensate victims’ families.
March: Then prime minister Tony Blair offers Colonel Muammar Gaddafi “the hand of friendship” following talks with the Libyan leader in a tent outside Tripoli.
The UK and Libya go on to sign a memorandum of understanding, with a commitment to negotiate a prisoner transfer agreement (PTA).
May: Oil giant BP and the Libyan government sign an exploration and production sharing agreement.
June: The Scottish Criminal Cases Review Commission (SCCRC) recommends Megrahi is granted a second appeal against his conviction after the first, in 2002, was refused.
December 19: It is revealed the UK Government has decided not to exclude Megrahi from the PTA.
September: Megrahi is diagnosed with terminal prostate cancer.
May 5: The Libyan government submits an application to the Scottish Government for Megrahi’s transfer under the PTA, followed by an application for release on compassionate grounds.
August 20: Then Scottish justice secretary Kenny MacAskill announces Megrahi is to be returned to his home country on compassionate grounds and he is freed from Greenock prison and taken to Glasgow Airport for a flight to Libya.
August 21: The UK and the US condemn the “hero’s welcome” given to Megrahi as he arrives in Tripoli to cheering crowds.
September 5: Then UK justice secretary Jack Straw acknowledges the prospect of trade and oil deals with Libya was “a very big part” of his decision to include Megrahi in the PTA.
An uprising begins in Libya which would see Gaddafi killed by rebels by the end of the year.
February 23: Libya’s former justice minister, Mustafa Abdel-Jalil, tells a newspaper he has proof that Gaddafi ordered the Lockerbie bombing.
April 8: Police continuing their investigation into the bombing meet former Libyan foreign minister Musa Kusa, who has apparently defected.
July 26: Megrahi appears in a televised pro-government rally in Libya and says his conviction was the result of a “conspiracy”.
May 20: Megrahi dies at home in Tripoli aged 60.
December 22: The UK, US and Libyan governments vow to co-operate to reveal “the full facts” of the bombing.
June 5: Six members of Megrahi’s family join forces with 24 British relatives of those who died in the atrocity to seek another appeal against his conviction in the Scottish courts.
December 20: Scotland’s top prosecutor Lord Advocate Frank Mulholland reaffirms Megrahi’s guilt and pledges to track down his accomplices.
July 3: Scottish judges rule relatives of the victims of the bombing should not be allowed to pursue an appeal on Megrahi’s behalf.
October 15: Scottish prosecutors announce they want two Libyans they have identified as suspects to be interviewed by police.
July 4: Megrahi’s family lodges a new bid to appeal against his conviction, five years after his death.
May 3: The SCCRC says a full review of Megrahi’s case will be carried out to decide whether a fresh appeal against conviction can be made.
November 21: A police investigation finds no evidence of criminality in relation to the handling of the Lockerbie investigation and prosecution.
March 21: The Crown Office reportedly questioned retired Stasi agents over the Lockerbie bombing, examining the possible role of the East German intelligence service in the 1988 bombing.
March 11: The Scottish Criminal Cases Review Commission rules a fresh appeal is to be allowed, and refers the case to the High Court of Justiciary.
June 3: The appeal against the conviction of Abdelbaset al-Megrahi is formally lodged at the High Court.
Nov 19: A crowdfunder is launched to help pay for the appeal.
Nov 24: The third appeal begins at the High Court in Edinburgh, sitting as the Court of Appeal, and lasts three days.
Dec 21: The US charges a “third conspirator” in connection with the Lockerbie bombing, on the 32nd anniversary of the atrocity.
January 15: Judges reject both grounds of appeal, meaning Megrahi’s conviction stands.