Thinktank tells Ukip departing from EU would cost UK economy £56bn

Open Europe thinktank warns Ukip that Britain could lose 2.23% of its GDP by leaving the EU customs union and single market

Britain faces a stark choice after an EU exit of allowing its economy to shrink by 56bn, by shutting down its borders, or agreeing to the continued free movement of European citizens in a new deal with Brussels, according to a leading thinktank.

In a challenge to Nigel Farage, who believes Britain can prosper outside the EU by blocking migration, the Open Europe thinktank warns that a unilateral UK exit could lead to a permanent dent in the country's GDP of 2.23% by 2030. This works out at 56bn a year.