Former business secretary Sir Jacob Rees-Mogg said: “The OBR is an unelected quango with too much control over government policy.
“It believes that mass migration is an unlimited boon to the economy.
„However, if you look at the recent decline in GDP per capita, it shows that the Open Door program has failed to deliver anything but a drop in wages and living standards.”
He added: „It's time the OBR's bogus forecasts are treated with the perspective they deserve, instead of being treated as holy writ.”
'It's a myth that the economy needs mass immigration'
Marco Longhi, Tory MP for Dudley North, said: “For the OBR to believe the value of open borders to be a huge benefit to the economy and overstate its value is a sad indictment of its forecasting abilities.
„I believe today's findings will go some way to dispelling the myth that the British economy cannot cope without hundreds of thousands of net migration each year.”
The OBR declined to comment on the CMC's analysis.
Writing for The Telegraph last month, David Miles, executive member of the OBR, said that one sure way to boost GDP is to get more people back into work.
„It is highly unlikely that sustained high levels of net immigration to increase the labor force can generate sustainable fiscal improvements,” he said.