Prison escapes have always made good copy for journalists and hard questions for ministers. Most people assume that home secretaries and justice ministers are personally responsible for locking up dangerous offenders, so that if the offenders get out of jail free, then the politician takes the rap. Charles Clarke, John Reid, Michael Howard, Roy Jenkins - all were deeply damaged by charges of lax security. In fact it is quite difficult to think of any minister with responsibility for prisons who has not been damaged at one stage or another by a fleeing jail-bird. On the other hand, they tend to wriggle free themselves. Michael Howard fired his top civil servant, but survived, after lax discipline let armed terrorists escape from Whitemoor prison. Roy Jenkins did not resign over George Blake, who spied for the Soviets and managed to escape from Brixton jail. Lord Prior did not resign when 38 prisoners escaped from the Maze. Kenneth Baker did not resign when two IRA remand prisoners slipped out, to the embarrassment of the Tory government.

So, there was something a little staged about Labour's attack in the Scottish Parliament yesterday on Kenny MacAskill, the Justice Secretary, over the escape of a violent criminal from an open prison. It helped that Brian Martin was known as “the hawk” and had been called “the most dangerous prisoner in Britain” - a title for which there is considerable competition. But the notion that Mr MacAskill had forgotten to lock the cell door, and was therefore personally responsible, did not carry the conviction needed to make the charge stick.

Iain Gray, the Labour leader, made a decent fist of it. “When he walked out of the open prison on Monday, Brian Martin was just three years into a 10-year sentence for firing a gun during a fight in a house in Fife,” he charged. “His previous offences included a string of armed robberies and threatening police with a sawn-off shotgun. This is a man once dubbed the most dangerous man in Britain. Will the First Minister agree that Brian Martin should not have been in an open prison in the first place?”

Fair question. Unfair answer: Alex Salmond quoted figures, about how more prisoners escaped under Labour than escaped under the SNP, presumably because with an SNP government around, more prisoners feel safer staying inside. “Any escape is greatly to be regretted,” he said. “But I don't think Iain Gray is on firm ground complaining about abscondees when the rate under this Justice Secretary is one fifth of what it was under the Labour Party.” I am not sure the word “abscondees” actually exists. But it is certainly better than Mr Gray's choice of vocabulary. He used “absconds” as a noun. Thus, an absconder who absconds becomes either an abscondee or an abscond, or else a thoroughly good reason for giving a justice minister a hard time.

But not so hard, I imagine, that we have to lock him up and throw away the key. Mr Gray tried hard, and Mr Salmond did little other than to repeat himself. Beside him, on the front bench, Mr MacAskill grimaced. And survived. For now.

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