A brain teaser for you. When it comes to releasing ailing prisoners on grounds of compassion, how would you describe the policy of Jack Straw, the justice secretary? Arm’s length? Devious? Fully reversible with a built-in spin mechanism, automatic back protection and an opaque finish? Compare and contrast the cases of Ronnie Biggs and Abdelbasset Ali Mohmed al-Megrahi.

Mr Biggs was a villain, albeit small time, but he never killed anyone. Following his role in the 1963 Great Train Robbery he was sentenced to 30 years. He escaped abroad but returned voluntarily to prison in 2001. Mr Megrahi was convicted of the Lockerbie bombing that killed 270 people. He was sentenced to 27 years. (Some believe his conviction was unsound but it still stands.) By last month Mr Megrahi had served eight years, Mr Biggs slightly longer. Both men were seriously ill and not expected to live long.