Philip Hammond's claim that the UK economy can expect a parliamentary backing for a check-style deal has won the backing of the International Monetary Fund.
The Washington-based organization said that it would expect a 1.5% growth in the UK's growth rate from 1.59 to expect 2019 for the European Union.
The IMF also backed up the chancellor's claim that the failure of the MPs would bring a deal to the EU.
IMF officials said they had not worked out the direct impact of Brexit on their most recent analysis, but it was clear that a hard brexit without a deal would harm the UK economy.
"A disruptive departure without an implementation period could have serious negative economic consequences," he said in its annual health check.
"While all the likely costs of the UK economy by departing from the frictionless single market that now prevails, an agreement that minimizes the introduction of new tariffs and non-tariff barriers would best protect growth and incomes in the UK and EU.
"Close cooperation and coordination with the EU to prevent disruptions and mitigate risks will be important to achieve a smooth transition," he said.
In his budget last month, Hammond said the economy would get a double boost from a check-style deal that almost replicated the current trade arrangements for goods across the EU.
He said the outlook for growth would improve, generating higher business profits and wages that would boost tax receipts, giving the government greater leeway to increase public spending and cut taxes.