MPs have expressed their 'alarm' that the government doesn't have even a 'basic policy' for post-Brexit international investment agreements.
It comes as No Deal chief Michael Gove said "we must operate on the assumption" that there will not be a Brexit deal on October 31.
Boris Johnson claimed weeks earlier that the odds of No Deal were "a million to one" and shot down Mr Gove's claim on a visit to Scotland.
But the new administration is already struggling to put forward a clear Brexit strategy - just 100 days from the deadline.
The report from the International Trade Committee ramps up fears that the UK will not be ready in time.
The cross-party group of MPs found that: "The Government was unable to set out even basic lines of policy" on the agreements.
"It needs to have a policy in place for the eventuality of a Brexit scenario in which there is no transition period - which could occur on October 31 2019," it warned.
"We are alarmed that no such policy seems yet to have been formulated. The UK cannot just go back to the approach it used before 2009."
According to the report, the Department told the Committee that it was prevented from formulating such a policy until after Brexit.
But the cross-party group of MPs say they have found no credible legal basis for this argument.
The report outlines a number of areas - including investment liberalisation and protection, and investment regulation - where there is little clarity on the Government's position.
Chairman of the committee Angus Brendan MacNeil MP said: "Outside the EU, the UK Government will have the responsibility of negotiating deals governing British investments abroad and overseas investments in the UK.
"International Investment Agreements have been hugely controversial in recent years - not least because of provisions relating to investment protection.
"Despite describing the value of investment to the UK as 'phenomenal', the minister for investment could tell us surprisingly little about the Government's approach to international investment agreements after Brexit.
"This is urgent, given that we could leave the EU without a deal in a matter of months, and if that happens the UK will take back responsibility for negotiating such agreements.
"My committee's report makes an unequivocal recommendation to the Government to adopt a policy on this as soon as possible."
A Department for International Trade spokesman said: "The UK is an incredibly attractive destination for foreign direct investment, as shown by a range of analysis by independent experts.
"As the Prime Minister has said, we are ready for no-deal. We are building on the 90 bilateral investment agreements we have already secured with countries across the world."
