The head of the CBI said Theresa May's Brexit deal "is not perfect" as internal emails revealed concerns in the business organisation about the plan.
CBI director general Carolyn Fairbairn said business had been "clear and honest" about the flaws in the deal but it was the best option available.
Her intervention came after ITV News published email exchanges within the top ranks of the organisation showing its Brexit specialist thought it was "not a good deal".
In its official response to the Political Declaration, CBI deputy director general Josh Hardie said: "It appears that we're on the cusp of a much-needed agreement. This shows a deal can be done and businesses across the continent will be watching this weekend's EU Summit closely.
This deal is not perfect – business is both clear and honest on this. But it is the best option we have for avoiding a cliff edge and building a pathway to a good future deal.
— Carolyn Fairbairn (@cbicarolyn) November 22, 2018
"The progress made is a credit to both sets of negotiators. But hard work lies ahead.
"A 20-page vision needs to become a 2,000-page agreement that secures trade and jobs before the spectre of no deal can be put to rest."
ITV reported, however, that Nicole Sykes, the organisation's head of EU negotiations, said there was "no need to give credit to the negotiators" in the statement "because it's not a good deal".
The message was inadvertently sent to the broadcaster at the foot of the official statement.
In its response to ITV, the CBI said the broadcaster "reproduced private debate knowing it's not CBI position".
"Responding to big announcements involves testing different views before issuing a public statement."
Ms Fairbairn said: "This deal is not perfect – business is both clear and honest on this.
ITN reproduced private debate knowing it's not CBI position. Responding to big announcements involves testing different views before issuing a public statement.CBI & members know deal's not perfect & hard work ahead, but right now it's the best option, protecting jobs & growth.
— CBI (@CBItweets) November 22, 2018
"But it is the best option we have for avoiding a cliff edge and building a pathway to a good future deal."
Support from the leading business organisation is valued in Number 10 as it seeks to persuade reluctant MPs to back the deal.
Liberal Democrat leader Sir Vince Cable said the CBI was trying to maintain a "polite approach to Government" but its members "see Brexit as damaging".
"The one thing that is persuading them to give some qualified support to the deal is the fear of no deal," the former business secretary said.
"However, this is the wrong approach. The Prime Minister has said that there are three paths we could take, her deal, no deal or no Brexit.
"The Conservatives should take no deal off the table, to end this damaging brinkmanship.
"Then the Government must give the people the final say on Brexit, a People's Vote with an option to remain in the EU so that businesses do not need to settle for a bad deal."
Labour MP Wes Streeting, a leading supporter of the People's Vote campaign for a second referendum, said: "Despite the CBI's public support, it is clear that even the Government's biggest business backers think this is a bad deal for Britain.
"There is no support in Parliament, among business or in the country for a deal which takes away control and makes people poorer.
"The British public deserve a real choice in a People's Vote between leaving the EU on these terms or sticking with the deal we've got inside the EU."