On 21st December 1988, Pan Am flight 103, a Boeing 747, took off from London bound for New York. Less than 40 minutes later, it exploded over the town of Lockerbie in the Dumfries and Galloway region of southwest Scotland. In all, 270 people from 21 countries were killed, including all 259 passengers and crew members, plus 11 people on the ground in Lockerbie. On 31st January 2001, after a belated three-year investigation, Abdelbaset al-Megrahi, an alleged former Libyan intelligence officer, was convicted of mass murder by a panel of three Scottish judges and sentenced to life imprisonment. He died in 2012 after being granted compassionate release on medical grounds and remains the only person to have been convicted of this attack. Although Libya initially denied any involvement, Colonel Muammar Gaddafi finally accepted responsibility for the atrocity in 2003. More than a quarter of a century after that fateful night, this crime remains the single largest aviation disaster in Britain’s history as well as its deadliest act of terrorism. This minute-by-minute account of events explores how an unaccompanied suitcase containing a Semtex bomb hidden inside a cassette player was transported on three separate flights before arriving at London Heathrow without being detected. The programme features archive footage, new interviews with key witnesses and personal accounts from family members who lost loved ones in the atrocity.