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Conservative plans to use the civil service to rubbish Labour’s spending plans have been scuppered after the shadow chancellor, John McDonnell, argued with senior civil servants that it would breach impartiality rules.

Tories blocked from using Treasury to attack Labour plans Read more

Forcing a climbdown before the general election, Britain’s highest ranking civil servant, Mark Sedwill, made a decision that the publication of Treasury analysis with only weeks to go before the 12 December poll would be improper.

The government had planned to open its election campaign with an attack this week on Labour’s economic credibility. However, opposition sources said the government had been slapped down by senior civil servants, forcing an embarrassing U-turn.

In an email exchange seen by the Guardian, the cabinet office told the party: “To confirm our conversation, these costings will not be published.”

A Labour source said: “This is an embarrassing slapdown to Tory ministers who were blatantly trying to use the civil service for political purposes.”