Britain will not seek a partial membership in the European Union that leaves it "half in, half out", Prime Minister Theresa May said on Tuesday, signaling she will push for a clean break from the 28-member bloc.

May's statement on her vision for "a Global Britain" was the clearest expression yet, since a majority of Britons voted to leave the union on June 23, of the government's intentions in Brexit negotiations with its EU partners.

"We do not seek to adopt a model already enjoyed by other countries," she said in a speech to foreign diplomats in London. "We do not seek to hold on to bits of membership as we leave."