Under the new regime, 60% of trade will come into the UK tariff free on WTO terms or through existing preferential access from January 2021, the government said.

The head of the International Monetary Fund said recent economic data for many countries was coming in below the fund's already pessimistic forecast for a 3% contraction in 2020.

The IMF's managing director, Kristalina Georgieva called on advanced economies to step up their efforts to help emerging markets and developing countries survive the economic and health impact of the pandemic.

Like previous outbreaks, the flu-like disease poses a risk to economies around the world as fear and confusion lead to abrupt changes in behaviour, decreased economic activity and a ripple effect across sectors that threatens everything from productivity to consumer prices.

The report said last year ended up having the slowest global economic expansion since the world financial crisis in 2008-2009.

Bank of Canada governor Stephen Poloz said slowing population growth is holding back economic growth and gains in productivity aren't happening fast enough to offset the change.

"I'm not looking at a tax cut now,'' he told reporters at the White House. "We don't need it. We have a strong economy.''

Global stock markets fell Tuesday after the International Monetary Fund lowered its outlook for the world economy, citing the impact of rising interest rates and trade tensions.

U.S. stocks rebounded in volatile afternoon trading on Tuesday, likely to be one of the most watched days on the markets in years.

Every major region in the world is experiencing an increase in economic growth going into 2018, but the World Bank warns it might not last.