Later, she said she would leave the Conservatives herself if Mr Rees-Mogg became leader. The former education secretary Justine Greening agreed: she too would find staying in under Mr Rees-Mogg “a bit of a stretch”. To appease them, Downing Street reiterated that Britain would leave the customs union. Nor is it possible, outside the customs union, to see how to protect the open border between Northern Ireland and the Republic. The single market has been conceded, and the benefits of membership of the customs union blurred.
Source: The Guardian February 06, 2018 18:22 UTC