Cardinal Keith O'Brien has defended the decision to free the man convicted of the Lockerbie bombing, saying that US politicians should not try to interfere in Scotland's domestic affairs.

The cardinal said that given the "steady rate" of executions in the United States, American lawmakers should "turn their gaze inwards, rather than scrutinising the working of the Scottish justice system".

He said Scotland's legal system had allowed Scottish Justice Secretary Kenny MacAskill to release Libyan Abdel Baset al-Megrahi last August "on compassionate grounds, following due process and based on clear medical advice".