Nicola Sturgeon has accused Theresa May of a "dereliction of duty" in failing to disclose the full economic impact of Brexit.
Scotland’s first minister made the criticism as the Scottish Government prepares to publish its own analysis of Britain’s withdrawal from the European Union.
Sturgeon said the research will detail how remaining in the European single market and the customs union would be the least damaging option for the UK economy.
The document comes as opposition parties ratchet up their campaign to prevent a hard Brexit, with Jeremy Corbyn coming under increasing pressure to get on board.
May’s Government has said it will seek to take Britain out of the single market and pursue a bespoke trade deal with the EU.
However the Scottish Government's study, to be unveiled in Edinburgh on Monday, will detail the impact of three different Brexit outcomes on GDP, trade and immigration: staying in the single market and customs union; a preferential trade agreement; or reverting to World Trade Organisation terms.
David Davis told MPs last month that the UK Government had not carried out any impact assessments of leaving the EU on the UK economy.
The Brexit secretary said "sectoral analysis" of different industries had been drawn up, but not a "forecast" of what would happen after Brexit.
Sturgeon said: "More than 18 months on from the Brexit vote, it beggars belief that the UK Government is not only still unable to say what kind of relationship it wants with the EU, but has also failed to produce any meaningful economic assessment of the different possibilities."
She added: "It will be a fundamental dereliction of duty as Prime Minister if Theresa May continues to pursue her red lines without providing information on their impact, and publicly discussing the options available.
"Of course, there is no alternative arrangement that can deliver the jobs, people and economic benefit that come from remaining members of the European Union but if the UK continues down the path of leaving the EU, it is the Prime Minister's duty to do as little harm as possible to the economy.
"The Scottish Government is absolutely clear that, if the UK is indeed leaving the EU, then it must stay within the single market and customs union to prevent needless job losses and cuts in living standards."
A UK Government spokeswoman said: ''We are seeking a deal that works for the whole of the UK, that delivers on the result of the EU referendum.
''Rather than trying to undermine the result of a democratic referendum, we urge the Scottish Government to work with us to ensure, as we leave the EU, we protect the UK's vital internal market."