The Government is fending off accusations that it has no clear plans for leaving the EU and lacks the resources to meet self-imposed deadlines, following the leak of a highly critical report into its handling of Brexit.
The leaked Deloitte memo claims Cabinet ministers are at loggerheads over negotiating strategies and Whitehall is facing a potential staffing shortage of 30,00 civil servants.
The document has been furiously dismissed by Downing Street sources, who argue it has “nothing to do with Government” and lacks any “credence”.
But its conclusions have been backed up by the respected thinktank the Institute for Government, which warns Brexit could prove “unsustainable” for some Whiltehall departments.
IFG researcher and former Deloitte employee Joe Owen said that while he may not recognise all of the accountancy firm’s figures, some of its claims did chime with the thinktank’s findings.
Writing on the IFG website, he said Whitehall has the “technical skills” required to deliver Brexit, but “does not have the capacity” on top of existing commitments.
“The work required to deliver Brexit has been described to us as an ‘existential threat’ to how some departments operate,” he said.
“Managing this whilst continuing to deliver existing priorities with the smallest civil service in decades is unsustainable.
“There is a huge amount of work already under way in both Department for Exiting the European Union and the rest of Whitehall.
“[But] failure to reveal the Government’s plan... is eroding confidence among business and investors, and encouraging unhelpful speculation about what the final destination might be.”
The assessment by Mr Owen came amid an ongoing row over the Deloitte memo, which came to light on Tuesday after it was leaked to the Times.
The document claimed that Cabinet splits are delaying the Government’s ability to agree a Brexit negotiating strategy, and that civil servants are struggling to cope with the workload and timetable.
A spokesman for the Prime Minister promptly disowned the memo, claiming it was “unsolicited” and “has nothing to do with the Government at all”.
She said Downing Street “[does not] recognise any of the claims it makes” and suggested it was the work of a firm “touting for busines”.
Deloitte has since confirmed that the report was not commissioned by any Government department and represents “a view of the task facing Whitehall”.
It went on to stress that the work was “intended primarily for internal audiences” and conducted “without access to Number 10”.
However, the senior civil servants’ union FDA said the memo appeared to confirm its fears that ministers are trying to implement Brexit “on the cheap”.
Chairman Dave Penman said there is a “deafening silence” from ministers over whether any additional resources will be provided to carry out the task.
He said: “Brexit on the cheap appears to be the Government’s preferred approach, but this will satisfy noone.
“Next week’s Autumn Statement is the Government’s opportunity to outline how it will provide the resources the civil service needs.”
Labour’s shadow Brexit secretary Keir Starmer said the report “is absolutely right” in claiming the Government does not have a plan.
SNP Europe spokesman Stephen Gethins said it offered a “staggering insight” into the “utter confusion and chaos” within the the Tory party.
But Tory MP Stuart Andrew critcised the document’s use of “questionable figures”.
He added: “The allegations of rifts forming in the Cabinet are simply wrong.”