Sir Keir Starmer has pledged to tackle the “overcautious” and “flabby” state to make it more efficient.

Writing in the Daily Telegraph ahead of a speech later, the prime minister insisted he was not interested in ideological arguments about whether the state should be bigger or smaller, adding: “I simply want it to work.”

The government has not put a figure on what size it wants the Civil Service to be but on Sunday Cabinet Office minister Pat McFadden said it “would and can” be smaller.

Unions have warned the government will struggle to compete for skilled specialists without offering higher pay.

“In such uncertain times, people want a state that will take care of the big questions, not a bigger state that asks more from them,” the prime minister wrote.

“The Civil Service has grown by 130,000 since the [Brexit] referendum, and yet frontline services have not improved. It’s overstretched, unfocussed and unable to deliver the security people need today.”

The current headcount of the Civil Service is more than 500,000.

Civil servants are politically impartial officials employed by the government, covering areas including policy development and services like benefits and prisons.

In his speech later, Sir Keir will link the need to reshape government to global instability which has pushed up bills at home, saying the state needs to be operating at “maximum strength”.

He will promise to cut the costs of regulation for businesses by 25% to boost economic growth.

His plan also includes greater use of artificial intelligence, underpinned by the mantra that civil servants should not be spending time on tasks where digital or AI can do it better and quicker.

The government gave the example of an AI helper for call centre workers, in partnership with Citizens’ Advice, which it said could halve the amount of time it takes call handlers to respond to complex questions.

New AI and tech teams will be sent into public sector departments to improve efficiency, with one in 10 civil servants working in tech or digital roles within the next five years.

Meanwhile, the PM will take aim at the “cottage industry of checkers and blockers slowing down delivery”.

Writing in the Telegraph, he said there had been “a tendency to avoid difficult questions by sweeping them under a carpet of regulation” to “outsource and delay decision-making and avoid accountability”.

“For any challenge faced, for too long the answer has been more arm’s-length bodies, quangos and regulators which end up blocking the government as we’re trying to build,” he added.

Earlier this week, the government said it would abolish the Payment Systems Regulator, which looks after Faster Payments and Mastercard, because it had increased costs for small businesses.

But the new Labour government has also set up more than 20 new arm’s-length bodies since winning power.

These include Great British Energy, which will invest in renewable energy to help meet the government’s clean power goals, and the Border Security Command, which aims to tackle small boat crossings.

Mike Clancy, general secretary of the Prospect trade union, which represents civil servants, said they were not “hostile to reforms” but more pay flexibility was needed to recruit and retain specialists in areas like science and data.

“Government should also be doing more to utilise the talented specialists it already has at its disposal, many of whom are working in regulators and other agencies that have been starved of funding in recent years,” he added.

He warned against the “incendiary rhetoric and tactics we are seeing in the United States”, where Elon Musk has pledged to take a “chainsaw” to the federal government and drastically cut the workforce.

On Wednesday a Labour spokesperson rejected characterisations of the governments plans as “taking a chainsaw to the system”.

“It is not about slashing the state, it is about reshaping the state so it works for working people,” they said.

Earlier this year, Sir Keir was criticised for saying “too many people in Whitehall are comfortable in the tepid bath of managed decline”.

However, in his Telegraph article the PM was keen to stress his criticism of the state was not aimed at individuals.

“The problem isn’t our fantastic civil servants – it’s the system they’re stuck in,” he wrote.

The Conservatives accused Sir Keir of having “no plan to reform the Civil Service or cut public spending”, criticising tax increases for businesses.

The Liberal Democrats said the PM was “tinkering around the edges while our economy continues to stutter”.