Accusations that civil servants are resisting attempts at post-Brexit reform are “crass” and damaging to morale, the government’s former top lawyer has said, after attorney general Suella Braverman said ministers were having to fight against officials’ “Remain bias”.

Sir Jonathan Jones, who spent six years as Treasury solicitor and head of the Government Legal Department, hit out at Braverman’s “generalised, unsubstantiated criticisms” following her interview with The Telegraph this weekend.

The attorney general told the newspaper that in both her current job and previously as a Brexit minister, she had found “some of the biggest battles you face as a minister are, in the nicest possible way, with Whitehall and internally with civil servants, as opposed to your political battles in the chamber”.

“That was something I didn’t expect, if I’m honest,” she said.

She said there is “an inability to conceive of the possibility of life outside of the EU” among civil servants that has hampered ministers’ attempts at reform.

“What I have seen time and time again, both in policymaking and in broader decision making, [is] that there is a Remain bias. I’ll say it. I have seen resistance to some of the measures that ministers have wanted to bring forward,” she said.

Jones – who resigned in 2020 over the government’s plan to use its internal market bill to back out of parts of its withdrawal agreement with the EU – said it was “crass” to suggest civil servants were trying to thwart government policy because of a political stance .

“Such generalized, unsubstantiated criticisms of civil servants are completely unfair and very damaging to morale and trust,” he told CSW.

“Brexit in any form would not have been possible without the tireless work of civil servants – on the necessary agreements, legislation and all the other preparation. This was all to deliver the policy of ministers (at least as it then was). Similarly it is for ministers to decide on – and own – post-Brexit policy.

“The idea that civil servants have been ‘thwarting’ anything is crash.”

Braverman said her comments should not be interpreted as “an opportunity to bash the civil service”, adding: “There are thousands of civil servants. In large part, they are brilliant. They work really hard. I’m supported, in particular, by a team of brilliant lawyers and officials at the Attorney General’s Office.”

However, her comments echo similar criticisms by ministers of officials’ perceived lack of enthusiasm for Brexit during the planning for the UK’s departure from the EU, which had a damaging effect on morale.

Responding to Braverman’s interview, FDA union chief Dave Penman said civil servants are to provide impartial advice and upholding the rule of law – and that “good ministers welcome this rather than dismiss it as politically motivated”.

And he mocked Conservative MP Lucy Allen’s description of Braverman’s comments as “brave”, noting that the civil service code prevents officials from publicly responding to criticism.

Yes Lucy, incredibly brave of one of the most powerful people in the country to attack civil servants for doing their job, knowing they’re not even allowed to defend themselves. Inspiring. https://t.co/IKCSytFKJ1

— Dave Penman (@FDAGenSec) July 3, 2022

Braverman even caught the attention of children’s book author Michael Rosen – an outspoken supporter of the civil service – who questioned “who can think of any government anywhere, anytime, attacking its own bureaucracy and/or professionals in order to appeal ‘over’ them in order to win allegiance from ‘the public’ or the ‘people’”.

re Suella Braverman’s attack on Civil Servants: hands up who can think of any govt anywhere anytime attacking its own bureaucracy and/or professionals in order to appeal ‘over’ them in order to win allegiance from ‘the public’ or the ‘people’. ..

— Michael Rosen (@MichaelRosenYes) July 3, 2022