PM May says Britain will leave customs union, to offer Ireland backstop

Prime Minister Theresa May said on Thursday Britain would leave the EU customs union after Brexit but a source said London was considering a backstop plan that would apply the bloc's external tariffs beyond December 2020.Asked about reports that London would ask to stay in the European Union's customs area beyond the end of a post-Brexit transition period in 2020, May denied she was "climbing down" on plans to leave."No. The United Kingdom will be leaving the customs union as we're leaving the E