THE Tories have been rapped by the UK’s most senior civil servant after trying to bring the neutral civil service into the General Election campaign, in a letter published by the Tory Party chair.

In the letter sent to Conservative chair Richard Holden, Cabinet Secretary Simon Case said the Tories needed to help in “protecting our impartiality” amid a spat over costings drawn up on Labour’s proposals.

The Tory chair had written to Case asking him to confirm that the Prime Minister did not lie when he said Labour’s election offer would cost an extra £2094 in tax to each household over the course of the next parliament.

In an ITV debate last week, Rishi Sunak had claimed that “independent Treasury officials” have costed Labour’s policies “and they amount to a £2000 tax rise for everyone”.

Senior Labour figures, including shadow chancellor Rachel Reeves, claimed this was a lie.

Pressure over the issue is believed to be one of the key reasons why Sunak decided to ditch a D-Day commemoration ceremony and instead return to the UK for an interview with ITV, which only further plunged his campaign into turmoil.

The £2000 figure comes from analysis by the impartial Civil Service of spending estimates about Labour’s policies provided by special advisers, who are political appointees of the Conservative Party in Government.

The right-wing Spectator magazine calculated that using the same methodology, the Tories’ proposals would cost each working household £3020. However, the magazine’s editor Fraser Nelson added: “This would be just as misleading as the £2000 figure that Sunak used.”

The Office for Statistics Regulation, which previously warned political parties to use figures appropriately during the campaign, has said the Conservatives have failed to make clear their calculations.

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In his letter, Case called on the parties not to drag the Civil Service into political rows during the General Election campaign.

“Upholding the impartiality of the Civil Service is a duty rightly shared by both the Civil Service itself and all political parties,” he wrote to Holden.

“I would therefore be grateful for your ongoing assistance, and that of your counterparts in other parties, in protecting our impartiality during the election period.”

Holden shared the letter on social media, claiming it showed the Tories were right to claim the £2000 figure for Labour was drawn up by civil servants.

Jonathan Portes, a professor of economics at King's College London, said the letter actually “confirms, as I and others have said, that claims by PM and others that costings were produced by ‘independent civil servants’ was a lie”.

“They were acting on instructions and using assumptions specified, in detail, by Conservative Ministers and special advisers.”

Dave Penman, the general secretary of the FDA trade union which represents public servants, said: “Actually Richard, [Case] confirmed that the costings were based on assumptions from ministers and special advisers.

“Maybe also dwell for a moment in the paragraph about your responsibility to uphold the impartiality of the civil service.”

Mikey Smith, the deputy editor of the Mirror, quipped to Holden: "I’d probably have read page 2 before tweeting it, but you do you."

Holden has found himself in hot water within the Tory Party after parachuting himself into a safe seat in Essex, 300 miles from the North West Durham constituency he represented from 2019.

The Conservative chair sparked ire from local campaigners in Basildon and Billericay, his new constituency, with Andrew Baggott, the Conservative group leader on Basildon council, saying he would not campaign for Holden.