So special advisers in the Scottish Government have cost £10million in 14 years.

That's a lot of Malcolm Tuckers. What do they spend all the money on, thumbscrews? Dictionaries of expletives?

Actually, the reality of the "spad" bears little resemblance to The Thick of It, in which monstrous spin doctor Tucker takes offence at being called a bully ("I'm so much worse than that," he growls). The prosaic truth is that special advisers are an important link between ministers and civil servants. Some focus on policy, some on the media, but hardly any threaten to remove people's entrails.

Special advisers have been around since the 1970s, but became controversial under Tony Blair. Alastair Campbell's overreaching power prompted concerns about their unelected might and the murky dealings of Damian McBride has tarred them all, unfairly, as political thugs. Yet ministers find them invaluable. David Cameron, George Osborne, and Ed Miliband are all former spads themselves.

Special advisers have a legitimate role, but ministers should be able to justify every appointment and cut numbers where possible - no matter what Tucker would say.