An influential MPs' committee has voiced "grave concerns" over the complacency of the Government's Department for Business in preparing for Brexit.
The department, headed by Business Secretary Greg Clark, is one of the parts of government most deeply affected by EU withdrawal, with responsibility for around one-fifth of the work streams requiring action.
But the chairwoman of the Commons Public Accounts Committee, Meg Hillier, said it appeared to be "operating in a parallel universe where urgency is an abstract concept".
With around a year to go to Brexit day on March 29 2019, the department had not begun procurement for at least 12 essential IT systems needed to replace EU databases for projects like the emissions trading scheme, said the committee in a report.
And it had made "virtually no attempt" to re-order existing priorities to free up time and staff for the massive job of ensuring a smooth Brexit.
The committee gave Mr Clark a two-month deadline to confirm which programmes can be stopped, paused or slowed down to make way for Brexit priorities.
Branding the delay in starting work on new IT systems "extraordinary", the cross-party group said it "doubted the realism" of the department's plans and was "extremely sceptical" that they would be delivered on time.
The department was "relying too heavily" on the proposed 21-month transition period which would delay the introduction of new arrangements until 2021, said the report, which stressed that new systems may be needed as early as next March if talks fail.
The Department for Business, Energy and Industrial Strategy (BEIS) was given an extra £35 million by the Treasury for Brexit preparations in 2017/18 and has recruited 305 of the 350 additional staff it believes are needed.
But the committee said it was "concerned" that the new recruits "lack the required level of experience and expertise".
Many of those hired are policy experts, leaving vital posts unfilled in areas like digital, where competition for specialist staff is fierce, the report warned.
It also repeated concerns about the Government's ability to get 1,000 pieces of secondary legislation - including 150 from BEIS - through Parliament in time for Brexit.
And it criticised BEIS for a lack of transparency about the work it is undertaking.
Ms Hillier said: "The Department for Business, Energy and Industrial Strategy appears to be operating in a parallel universe where urgency is an abstract concept with no bearing on the Brexit process.
"We have grave concerns about this apparent complacency, compounded by the lack of transparency on the department's progress with what in some cases will be critical projects."
Meanwhile, a separate report by the Institute of Economic Affairs think-tank and trade association Acita urged the Government to take practical steps now to prepare for withdrawal from the EU's customs union.
The report called for investment in infrastructure at borders to handle the expansion of customs controls, as well as additional resources for HM Revenue and Customs to support companies dealing with the new arrangements.
Self-assessment schemes should be introduced to limit the expected increase in customs declarations which HMRC will have to cope with, the report said.
A BEIS spokesman said: "Along with the whole of government, BEIS is focused on getting the best deal for the UK and ensuring a smooth transition for businesses, consumers and workers.
"Since this report was written, BEIS has received £185 million of extra funding to help deliver a successful Brexit by employing an increased number of staff on our Europe work, identifying the most pressing legislative challenges and remaining ahead of schedule by recruiting high-calibre staff to ensure we prepare thoroughly and effectively."