London Mayor Sadiq Khan has called for a second Brexit vote, criticising the government's handling of Brexit negotiations with the 28-member European Union.

Writing in the Observer daily on Sunday, the Labour politician said that with the UK due to leave the EU in six months, it now faced either a "bad deal" or "no deal", the BBC reported. The debate had also become "more about (former Foreign Secretary) Boris Johnson's political ambitions" than what was good for the UK, he said.