Britain can secure trade deals worth twice the amount of those signed by the European Union if it adopts a more extreme form of Brexit, leading Eurosceptics have said.

Change Britain, a group co-founded by Michael Gove and endorsed by Boris Johnson, has discovered that 14 countries have publicly expressed interest in an agreement after Brexit.

The nations have economies that total around £17 trillion – twice the size of those countries who already have a trade deal with the EU.

However, the UK can only capitalise on that potential if they decide to opt out of the customs union, the group warns.