Throughout the Brexit negotiations, the EU-Canada Comprehensive Economic and Trade Agreement (CETA) has been proposed as a model for the UK’s future relationship with Europe. 

A deal like Canada’s would eliminate most tariffs and deliver control over immigration and trade policy.  However, outside a customs union, the UK would face customs declarations and a hard border between Ireland and Northern Ireland.  The services sector (80% of UK GDP output), would also face much reduced access for trade.  And the lack of a common rule book would create a number of serious regulatory barriers.