Right-leaning Spectator Magazine has applied Rishi Sunak’s maths to the Conservative’s spending plans – finding the average household would be £3,000 worse off under a Tory government.
Ministers have been advised to stop asking civil servants to tot up their rival parties’ policy proposals after a row over a Tory attack line – that Labour would raise taxes by £2,000 per household over four years – broke out.
Lord Gus O’Donnell said opposition policy costings are among the “grubbiest processes” in Whitehall after Sunak used figures he claimed were based on costings by HM Treasury to rubbish Labour’s plans for the country.
Speaking to BBC Radio 4’s World At One, Lord O’Donnell described opposition policy costing exercises as “an attempt by politicians … to buy credibility from the Civil Service, because the Civil Service is required in its everyday work to be honest and objective”.
The crossbench peer, who was permanent secretary for the Treasury before he became cabinet secretary, the most senior civil servant, until 2011, said: “Ministers tell you to produce these costings on some assumptions they give you, which are dodgy assumptions designed to make the policy look as bad as possible.”
He added: “(Opposition policy costing exercises) to be honest are one of the grubbiest processes I’ve ever been involved in, and I hope to goodness that a future government will stop doing this because they’re done by both parties, right? Conservative and Labour have done them, I’ve done them – many of these during my career.
“I hated every second working on these.”
Labour’s shadow attorney general Emily Thornberry said the row had “so undermined the office of prime minister” after Mr Sunak said on ITV that “independent Treasury officials” had costed Labour’s policies “and that they amounted to a £2,000 tax rise for everyone”.
Several media commentators have also hit out at the use of phony figures, with The Spectator using Sunak’s own methodology to cost how much Tory proposals would cost per household and finding it would be embarrassingly more.
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