Three Conservative prime ministers have led the UK government since 2010 and all three departed involuntarily from Downing Street. David Cameron, instigator of the Brexit referendum, resigned promptly on 24 June 2016, the morning after its defeat. His successor Theresa May had choices for British economic policy compliant with the referendum result, which was a 52%-48% majority for Brexit, but with the ballot paper offering just a binary Leave/Remain choice. There was no detailed plan and the UK could have quit the EU while maintaining preferential trading links.
Non-member Norway is effectively a member of the single market, another non-member Turkey is attached to the customs union, while Switzerland adheres to a complex set of bilateral regulatory and customs arrangements. All three enjoy many of the trading benefits of membership from outside the union.