Given the trouble they cause, you might wonder why senior politicians bother employing special advisers, or "spads" to use the shorthand.
Think of Alastair Campbell, Tony Blair's irascible spin doctor and the "dodgy dossiers" on Iraq. Or Damian McBride, Gordon Brown's spad, who resigned in 2009 after conspiring to smear Tory politicians on the internet.
After that, Mr Brown came out with the oxymoronic sound bite. "I take full responsibility for what happened, which is why the person responsible went immediately." Then there was the former News of the World editor, Andy Coulson, David Cameron's special adviser who had to resign last year over the phone hacking affair, raising serious questions about Mr Cameron's judgment in employing him in the first place.
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