Pictured: Rachel Wolf, the co-author of the Conservative Party's election blueprint

Civil servants could be prevented from switching jobs every 18 months as part of 'seismic' changes that Downing Street will bring in once Britain has left the EU, the architect of Boris Johnson's manifesto claimed today.

Rachel Wolf, the co-author of the Conservative Party's election blueprint, said the PM and his chief aide Dominic Cummings want to run 'the most dynamic state in the world'.

As part of a large-scale transformation, age-old practices will be axed and the civil service will be modernised from top to bottom, she said.

Ms Wolf said they would end the 'merry-go-round' of officials changing jobs every 18 months.

Critics claim the revolving door policy prevents civil servants from building up expertise and also allows them to escape the consequences of their mistakes.

She warned many officials 'cannot believe the PM and Dominic Cummings mean business' and 'as a result, they seem woefully unprepared for what is coming'.

But unions complained that it was wrong to paint the civil service as 'antiquated or resistant to change'.

They also argued that switching jobs was often the only way workers could get a pay rise.

Ms Wolf said Boris Johnson (pictured) and his chief aide Dominic Cummings want to run 'the most dynamic state in the world'

Ms Wolf, who has her own communications firm Public First, said anyone staying in the same job for longer than 18 months is currently seen to have 'stalled' in a culture that 'kills institutional memory and expertise' and ensures that 'everyone rises to their position of incompetence'.

Writing in The Daily Telegraph, she said plans for merging, creating and abolishing departments represented just a 'tiny fraction' of what was planned.

Such changes are likely to be implemented in the spring once the UK has left the European Union.

Ms Wolf has also rubbished the idea that the civil service would become 'politicised' under the new regime.

She claimed anybody including socialists would be welcome if they can 'deliver trains on time or figure out nuclear fusion'.

Mr Cummings, the former Vote Leave mastermind who is now regarded as the most powerful unelected official in the country, is a long-standing critic of the way Whitehall is run.

'Cummings has been reading and thinking about how to transform the public sector for two decades', Ms Wolf wrote (Pictured: Dominic Cummings)

He has moaned in the past that civil servants are rarely fired and are allowed to leave early or take holiday during times of crisis.

'Cummings has been reading and thinking about how to transform the public sector for two decades', Ms Wolf wrote. 'He does not think it is a distraction, but a prerequisite to delivering even the simplest promises'.

She added: 'Without changing how government operates, the Prime Minister cannot deliver 50million new GP appointments, new train lines or better bus services. All this and more was promised in the election manifesto (which I helped write) and is crucial to new Tory voters'.

Dave Penman, head of the FDA union for senior civil servants, told PoliticsHome: "Whilst those advocating reform may like to paint the civil service as antiquated or resistant to change, the reality is somewhat different.

"The UK civil service, recently ranked first in an international analysis of effectiveness, has had to constantly reform and adapt as each government sets out its new priorities.'

Prospect deputy general secretary Garry Graham said: “Some of the ideas mooted so far such as looking to reduce churn in job roles are clearly vital.

'However government needs to realise that churn is often the result of poor pay and reward and staff development structures and take steps to ensure people can develop and get a decent pay increase without needing to change jobs regularly.'

Ms Wolf wrote the Tory manifesto with Downing St policy chief Munira Mirza.

How workers are recruited and trained is likely to be one of the big changes to the system, she said.

As it stands, just 17 per cent of fast-stream recruits have science-related degrees.

She predicted that employees could be made to sit exams to make sure they can grasp data science and forecasting.