Truth about Lockerbie bombing 'may never be known'

The truth behind the Lockerbie bombing may never be known, says a former British ambassador to Libya.

Only one man, Abdelbaset al-Megrahi, was convicted of the bombing when he was found guilty in January 2001 and given a life sentence. He was diagnosed with prostate cancer in 2008, leading to a decision to free him from Greenock prison under compassionate release rules.