Government analysis forecasting that any outcome from Brexit would damage economic growth will be shared with MPs.
Ministers were forced into agreeing to release the document after coming under parliamentary pressure from Labour and critics on the Tory benches.
The move is in stark contrast to comments Prime Minister Theresa May made en route to China when she said making the leaked documents public would be “wrong”.
But the analysis will only be made available to MPs and will not be published more widely.
Ministers did not oppose Labour’s bid to force the document to be disclosed.
Meanwhile a Government minister who publicly suggested the forecasts could change the whole approach to Brexit was rebuked by Chief Whip Julian Smith.
Justice minister Phillip Lee was called in after he tweeted that if the figures in the leaked assessment are “anywhere near right”, there should be a “serious question over whether a government could legitimately lead a country along a path that the evidence and rational consideration indicate would be damaging”.
Justice Minister Phillip Lee was called in by the Chief Whip (Parliament/PA)
The papers prepared by the Department for Exiting the EU and obtained by website Buzzfeed suggested that, even with a comprehensive trade deal, UK growth would be down by 5% over the next 15 years.
This would rise to 8% if Britain left without a deal and was forced to fall back on World Trade Organisation rules.
Faced with Labour’s use of a parliamentary procedure to force the Government to release the document, Brexit minister Robin Walker confirmed it would be handed to the Exiting the European Union Select Committee.
But Mr Walker urged the committee against making the analysis public, describing it as preliminary, “unfinished” and said there are aspects of it which “remain negotiation-sensitive and should not be put in the public domain”.
He also said the document contains a “large number of caveats”, adding it is “not yet anywhere near being approved” by ministers.
Government sources said the document was “incomplete” and “produced without ministerial sign-off”.
But Downing Street said the PM had seen a first draft of the analysis last week.
A spokesman said: “It is right, and it is correct for the civil service to prepare these sorts of analyses to help inform the Government’s decision as the end state negotiations continue.”
Number 10 made it clear Brexit minister Steve Baker would not be reprimanded after telling MPs on Tuesday that official forecasts drawn up by civil servants were “always wrong”.
Asked why Mr Lee had been disciplined over his remarks but not the Brexit Minister, a Government spokesman said Mr Baker’s comments were made in a statement to the Commons, while Mr Lee had been “speculating” on leaked documents.
A Government spokesman said of Mr Lee: “He has been spoken to by the Chief Whip and been reminded it is best to air views in private.
“It is the fact that he aired it in public. That it was speculating about a leaked document in public.”
Downing Street said the partial analysis had not modelled Mrs May’s preferred outcome of a bespoke deal with the EU.
Earlier, the PM dismissed the significance of the leaked Government studies.
Mrs May said the findings were “very preliminary” and did not address the prospect of a bespoke deal.
She said: “It would be wrong to publish analysis before that analysis has been completed, and it would also be wrong to publish analysis which might prejudice our negotiating position, and indeed Parliament itself has accepted that.”
Commons Speaker John Bercow said the report should be made available “as a matter of urgency”.
Shadow Brexit secretary Sir Keir Starmer said: “I look forward to studying the documents in full and helping to ensure that in future Brexit policy is driven by evidence, not ideology.
“It’s time the Prime Minister reflected on her reckless red lines that are clearly not in the national interest.”