The International Monetary Fund has downgraded its forecast for UK economic growth over fears of disruption if Britain votes to leave the European Union on June 23.

In its World Economic Outlook, the global financial body warned that Brexit could inflict "severe regional and global damage" by disrupting trade relations.

Negotiations over post-exit arrangements would probably be "protracted", leading to an "extended" period of uncertainty and market volatility.

The IMF scaled back its projection of UK economic growth for 2016 by 0.3 percentage points to 1.9% - marginally below the 2% forecast of the Government's Office for Budget Responsibility - but held its forecast for 2017 at 2.2%.

The IMF's downgrade comes on the same day of an ICM poll suggesting the 'exit' camp is ahead by three percentage points.  According to the poll, support for Britain to leave the European Union stands at 45 percent.

The poll of 2,030 people, conducted between April 8 and 10, found that 12 percent of those surveyed were undecided. The ICM's previous poll had the 'remain' camp ahead by one percentage point. 

Chancellor George Osborne said the IMF's report represented a "stark" warning of the risks of UK withdrawal from the EU in the referendum. But shadow chancellor John McDonnell said Mr Osborne's failure to meet his own economic targets had also played a part, and it was time for him to "change course".

Campaigners for UK withdrawal rejected the IMF analysis and accused the international body of "talking Britain down" at Mr Osborne's request.