The British Government has denied claims that it has no Brexit plan and very little understanding of what leaving the EU means for industries.
A leaked memo for the Cabinet Office from external accountancy firm Deloitte, accused Theresa May's government of being unprepared for the UK to leave the EU.
The memo, dated November 7, which has been obtained by The Times, also suggests that splits between Cabinet members are delaying the Government's ability to agree a negotiating strategy prior to triggering Article 50.
However, ministers have disowned the memo, with the Prime Minister's spokeswoman saying she "wholeheartedly" disputes the claims.
She said: "We do have a plan, so I dispute that wholeheartedly. We have set out what the timetable will be, that is less than six months before triggering Article 50."
Titled "Brexit update", the memo criticises Mrs May for "drawing in decisions and details to settle matters herself".
It also warns that big firms will "point a gun at the government's head" to get reassurances for better trading conditions after Brexit as car manufacturer Nissan did.
According to the paper, the memo said: "Every department has developed a 'bottom-up' plan of what the impact of Brexit could be - and its plan to cope with the 'worst case'.
"Although necessary, this falls considerably short of having a 'Government plan for Brexit' because it has no prioritisation and no link to the overall negotiation strategy."
Deloitte said the note was "intended primarily for internal audiences."
It added: "It was not commissioned by the Cabinet Office, nor any other government department, and represents a view of the task facing Whitehall. This work was conducted without access to No. 10 or input from any other government departments."
According to The Times, it said the Government could take another six months to figure out its priorities, adding: "Despite extended debate among (department) permanent secretaries, no common strategy has emerged.
"It is likely that the senior ranks in the civil service will feel compelled to present potential high level plan(s) to avoid further drift.
"Departments are struggling to come up to speed on the potential Brexit effects on industry. This is due to starting from a relatively low base of insight and also due to fragmentation."
The memo also suggested that the government does not have enough officials to be able to implement Brexit quickly, with departments developing plans resulting in "well over 500 projects".
A Government spokesman said: "This is not a Government report and we don't recognise the claims made in it. We are focused on getting on with the job of delivering Brexit and making a success of it."