The true scale of immigration to the UK has been underestimated by at least 50,000 people a year, a new analysis has suggested.

Migration Watch UK, the campaign group, said that net migration may now be as high as 375,000 a year because more Eastern European migrants have come to this country than previously thought.

The Office for National Statistics will next month publish the results of an official review of migration figures on the eve of the EU referendum.