Setting out the scale of the challenge, the civil service chief executive reminded the Prospect civil service seminar that two new departments had been created in the wake of the EU referendum result, with another two having been merged.

He said that a department such as Defra was already undergoing huge reorganisation before the vote and “all of a sudden 90% of its business has changed”.

While recognising that the government could not provide a “running commentary” on its Brexit position he said that businesses nevertheless needed to make investment decisions and that an understanding of red lines was needed.

Critical skills gaps

Manzoni, also the permanent secretary for the cabinet office, acknowledged earlier in his address that the civil service was “critically short of skills in certain areas”. He said that “skills associated with delivery have been allowed to atrophy” and that they needed to be rebuilt.

New skills in digital applications were also needed, he said, not least because the civil service was “a decade behind with technology”. Manzoni also spoke of the need for the service to better reflect the diversity of Britain and that new structures and career paths were needed to attract the right skills.

He added that as part of this the civil service needed to be “more permeable”, encouraging people back to the service having gained skills and experience elsewhere.