George Osborne's claim the United Kingdom's economy would shrink by 6% by 2030 if it left the European Union has been attacked by pro-Brexit Tory MPs.
Today the chancellor said Britain "would be poorer by £4,300 per household" if it left the EU at the June 23 referendum.
But Tory energy minister Andrea Leadsom said the Treasury's claim was "unpatriotic" and dismissed the figures as "unfair and biased".
Tory MPs also used Twitter to attack the chancellor and the 'Remain' campaign.
Conservative MP Stewart Jackson mocked up his own version of the Treasury analysis.
Former cabinet minister John Redwood told BBC Radio 4's Today programme that Osborne’s claim was "absurd".
Bernard Jenkin said the chancellor "should be ashamed of himself". He told Sky News given Osborne had originally said he would balance the Budget by 2015 "his forecasts are not reliable".
And Peter Bone MP said "the Treasury failed to predict the most severe financial crisis in living memory. What makes them think they can predict the state of the economy in fourteen years’ time?".
In his speech today, Osborne said today that well as that long-term impact, in the short term the country would face a "profound economic shock and real instability".
He said the analysis produced by the Treasury was "serious and sober" and showed "British families will pay a heavy economic price if we leave the EU."
"And the price would be paid by British families. Wages would be lower and prices would be higher," he said.
"The most likely result is that Britain would be poorer by £4,300 per household. That is £4,300 worse off every year, a bill paid year after year by the working people of Britain."
Speaking alongside Osborne today, pro-EU environment secretary Liz Truss said the referendum was more important than "internal bickering" in the Tory party.