A British exit from the EU would not imperil international trade deals, a group representing 'vote leave' lawyers said today.

Lawyers for Britain said its research countered claims by the remain camp that Brexit would result in years of uncertainty while the UK renegotiated international trade agreements. 'This is not supported by the facts or the evidence,' the group said. 

According to the report, uncertainty over future trade with the EU could be resolved by the UK rejoining the European Free Trade Agreement (EFTA), of which it was a founder member.

'We could apply to re-join with effect from the day after Brexit.

'There is no reason why the four current EFTA countries would not welcome us back, given that the UK is one of EFTA’s largest export markets. EFTA membership would allow us to continue uninterrupted free trade relations with the four EFTA countries, and also to participate in EFTA’s promotion of free trade deals with non-member countries around the world.'

Deals with countries outside the EU could be maintained simply by the UK continuing to apply the substantive terms of these agreements after exit, unless the counterparty state were actively to object. 'We can see no rational reason why the counterparty states would object to this course since that would subject their existing export trade into the UK market, which is currenlty tariff-free, to new tariffs,' the report says.

'There will be no need for complicated renegotiation of these existing agreements as misleadingly claimed by pro-remain propagranda.'

Meanwhile, the UK would be able to participate in new trade agreements with non EU members from the day after exit. 'The process of negotiating new trade deals can be started during the two-year notice period leading up to Brexit, with a view to bringing them into force on or soon after the date of exit,' the report states.  

Earlier this year rival group Lawyers in for Britain warned that a free trade agreement between the UK and the EU might take years to negotiate – and that deals with third countries would no longer apply.