Boris Johnson's Brexit deal would make every person in the UK £1,100 poorer a year on average, a leading economic forecaster has warned in a damning report.

Axar.az reports citing foreign media that the National Institute of Economic and Social Research found that the prime minister's withdrawal plan leave the UK £70 billion worse off a year and shave nearly 4% off the economy by the end of the 2020s.

The research comes after MPs voted on Tuesday for a snap general election on December 12, and is one of the first independent assessments of how the economy would perform under Johnson's plan, which he agreed with EU leaders last month.

NIESR estimated that Britain's economy would be 3.5% smaller after 10 years than if it remained in the EU, the equivalent to losing the entire economic output of Wales.

"We don't expect there to be a 'deal dividend' at all," said NIESR economist Arno Hantzsche. "A deal would reduce the risk of a disorderly Brexit outcome but eliminate the possibility of a closer economic relationship."