“Civil servants are already at breaking point dealing with reductions in staff numbers, an increasing workload and uncertainty over the government’s position on Brexit," said Sue Ferns, deputy general secretary, speaking on behalf more than 27,000 skilled workers across government departments and agencies.

“The NAO report echoes our own evidence that the workload faced by specialists, professionals and managers in the civil service, who will be expected to lead on the detailed work on Brexit, is too great.

“The UK risks losing out in Brexit negotiations, and making the wrong decisions on key areas of policy set to be transferred to us when we leave the European Union, unless Ministers ensure we have the staff and the skills we need to do the job,” she added.

The NAO found that senior recruitment competitions run by the Civil Service Commission in 2015-16 resulted in 34 out of 158 posts (22%) remaining unfilled. Many of these were for posts requiring specialist commercial or digital skills.

Ferns pointed to the Civil Service Commission’s finding that pay is a barrier to recruitment. That is why Prospect is calling for an independent review of civil service pay.

“The government is living in cloud cuckoo land if it thinks it will be able to recruit the specialists it needs on salaries that just don’t compete with the private sector.

“We agree with the NAO that the scale of the challenge means there is a need for greater urgency to grow skills in the civil service – particularly given that the work of government is becoming ever more technical.

“However, asking the civil service to deliver more, even though it has reduced in size by 26% since 2006, is unrealistic.

“We are also concerned, and agree with the NAO, about the age profile and the pipeline of talent and skills – 40% of civil servants are now aged 50 or over,” added Ferns.

The NAO said: “Departments told us that this was a particular issue with specialists, many of whom may retire in the next five to 10 years.”

Brexit

In summer 2016, a Cabinet Office cross-government EU exit capability review found that 12 of the 17 then main departments identified a ‘considerable’ or ‘significant’ impact to their capability in policy, operational and specialist skill areas.

“This chimes with a recent survey carried out by Prospect where only one in five respondents said the civil service has the skills it needs to handle Brexit,” Ferns concluded.