Lawmakers were expected to vote later on Wednesday against a leaving the European Union without a transition deal, then vote on Thursday on seeking a delay to Britain's departure, now scheduled for March 29.
The thinktank also warned that it could not determine whether austerity was ending and public services moving "decisively upwards after almost a decade of unprecedented cuts" until the conclusion of the chancellor's spending review, which will be unveiled alongside the autumn budget later this year.
"Leaving with no deal would mean significant disruption in the short and medium term and a smaller, less prosperous economy in the long term, than if we leave with a deal", Mr Hammond said in his speech to parliament.
Last night's vote leaves a cloud of uncertainty hanging over our economy. "That is not what the British people voted for in June 2016", he said.
The problem facing Hammond is that the OBR forecasts were prepared on the assumption that Britain leaves the European Union on March 29 in a smooth and orderly fashion. Chamber chief executive Ann McGregor said: "Derry/Londonderry will welcome Philip Hammond's comment that the negotiation of a City Deal for Derry is "progressing", despite him failing to provide further details".
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Samuel Tombs, chief United Kingdom economist at Pantheon Macroeconomics, said: "The lower borrowing forecast primarily reflects an upward revision to the forecast for income tax receipts and a reduction in the forecast for debt interest payments, following the recent fall in gilt yields". "Little appetite remains among MPs or the wider public for more austerity".
"In recent weeks survey indicators of current activity have weakened materially, in part reflecting heightened uncertainty related to Brexit", the OBR said. More than anything, today's statement had a very clear motive: "to dangle the prospect of a deal dividend in front of MPs who may still change their mind and vote for Theresa May's Withdrawal Agreement if it comes back for a third time".
Mr Johnson said there was a consensus among economists that the United Kingdom economy would have been about 2% bigger had the Brexit referendum not occurred. "It must be avoided".
He added: "There's plenty that needs fixing and there are ways of raising more revenue, but they need to be carefully thought out and implemented if they are to be both effective and fair".