Businesses have paid a "heavy price" for ministers not speaking to them more about the government's Brexit plans, the head of Parliament's spending watchdog has told MPs.
Sir Amyas Morse accused ministers of underestimating how well the business community would have coped with planning for different outcomes of the talks with Brussels, leaving many in a "difficult position".
Sir Amyas, head of the National Audit Office, also warned there will be "points of failure" in the Whitehall machine when the UK leaves the EU, as the task of preparing for Brexit is so huge.
Downing Street hit back at the claims, insisting meetings had been held with business groups as the government formulated its negotiating stance.
Speaking to the Brexit select committee, Sir Amyas said: "Is it a good thing that there hasn’t been clearer communication with business? I think it’s been driven by a desire to not cause uncertainty and concern in the business community, but I think it has carried a heavy price with it.
"I think government could have told stakeholders more and I think it would have been positive if they had.
"But I understand their argument for not doing it, which is that it would only cause ferment in the business community, but I think they underestimate the capability and the maturity of the business community quite a bit.
"They are actually very good at running their businesses and if you don’t give them a chance to plan ahead and to solve the problem, you are putting them in a very difficult position.
"And I think many businesses are going to find themselves in a relatively difficult position."
In July 2017 Sir Amyas claimed the government's Brexit plan could "at the first tap" fall apart "like a chocolate orange" as it called on more joined-up work across Whitehall.
Speaking on Wednesday, the NAO chief was still critical of the way government had set about planning for Brexit.
He said: "There is so much concentrated risk. When you think about it, if you pardon my saying it, you wouldn’t start from here.
"You have a lot of things going forward in very short timescales.
"Generally speaking, the civil service is putting a terrific effort behind this. But because of the large number of unresolved risks that will be there at March, some of those are bound to come to reality.
"So rather than saying 'it will fall apart like a chocolate orange', what will happen is there will be points of failure."
Asked about the comments, the Prime Minister's Official Spokesman said: "I wouldn't agree with that at all.
"We have held a series of roundtables with business throughout the Brexit process.
"We've communicated with them throughout and obviously we are currently going through the process of issuing a series of technical notices for all of the relevant stakeholders which of course include business."