He also signalled that ministers eventually want to go further, slashing the headcount back to 2015/16 levels, which would be a reduction of as many as 70,000 roles.

Mr Clarke said last month that increases in civil service headcount had become “impossible to justify long-term and something we’re determined to reverse”. Recent increases to the headcount have completely reversed the cuts during the austerity era.

In a speech setting out plans for a slimmed-down Whitehall, he said: “Through a scrupulous focus on efficiencies, more streamlined processes, and a better matching of our people to our priorities, we will bring civil service headcount down to sustainable levels for the longer term, and this will be a focus of the years leading up to the next Spending Review.”

However, the FDA warns many of the roles will be difficult to reverse given Covid backlogs and that power has permanently moved from Brussels after Brexit.

“A lot of health staff were brought in to deal with Covid and now you’ve got the legacy of it,” Mr Penman said, highlighting backlogs in health and the courts.

“What’s quite disappointing about some of the stuff that Rees-Mogg and Clarke were saying is they are fixating on this number of civil servants that have increased over the last five or six years and really that’s because the demands of the civil service have increased.”

The Government wants to move 22,000 civil servants out of London by 2030.

However, the expansion in recent years was largely concentrated in London as more staff were taken on to help with policy.

The disproportionate increases in the capital came despite promises by ministers to move decision makers out of London as part of the levelling-up drive.

Whitehall faces radical shake-up as minister promises a ‘quiet revolution’ 

By Tom Rees 

Whitehall mandarins could be forgiven for feeling a bit more secure after the sudden departure of Dominic Cummings from the heart of Government.

The Prime Minister’s former chief adviser had an overhaul of the civil service firmly in his sights after dubbing the bureaucracy “an idea for history books” and calling for its permanent secretaries to be scrapped. 

“What SW1 needs is not more drivel about ‘identity’ and ‘diversity’ from Oxbridge humanities graduates but more genuine cognitive diversity,” he said in one of many diatribes launched against mandarins before leaving in November 2020.

But while the threat of a Cummings-led upheaval has vanished, the idea of a sweeping shake-up in Whitehall has outlived the adviser’s reign in Number 10.

Treasury number two minister Simon Clarke is promising a “quiet revolution” in Whitehall, after Michael Gove last year launched plans to reform the running of Government. As civil servants face a rude awakening after a huge expansion in headcount, a London-based lifestyle and years of homeworking, there are worries the upheaval might damage the flow of Government operations. 

Speaking at the small state think tank the Institute of Economic Affairs late last month, Clarke outlined his ambitions to trim the fat off the state and return civil service numbers to pre-Covid and even pre-Brexit levels.