The survey of 1,073 Prospect members working in the civil service or for government agencies found that fewer than 5% of civil servants were satisfied with the government’s approach.

Members were also asked if they were confident that a good Brexit deal could be negotiated, with 77% of civil servants saying they were either ‘not confident’ or ‘not confident at all’ and under 6% saying they were either ‘confident’ or ‘very confident’.

A separate survey by the union from March 2017 found that 19% of civil servants were satisfied with the government’s Brexit approach, indicating a significant loss of confidence from civil servants over the last 18 months.

Prospect represents civil servants in a number of government departments including Defra, the Ministry of Defence and the Department for Transport as well as in government agencies such as the Office for Nuclear Regulation, the Met Office and the Civil Aviation Authority.

Prospect general secretary Mike Clancy said:

“Our civil service members are experts in their fields, the lack of confidence they have in the government’s approach to Brexit should be sounding alarm bells at the highest levels of government.

“We are now only months away from exit day and we are still no clearer on the government’s plans in vital areas of policy, it is no wonder that experts have such little faith in the government’s ability to get a good deal.

“There is still time for the government to adopt a more sensible and evidence-based approach, but government ministers need to spend less time deriding expertise and accusing civil servants of having biased agendas, and more time listening to the people who know what they are talking about”.