LONDON, June 23, 2016 (Xinhua) -- Britain's Prime Minister, David Cameron and his wife Samantha leave the Central Methodist Hall polling station after casting their votes for the EU Referendum in London, on June 23, 2016. Millions of Britons will vote to stay in or leave the European Union (EU) on Thursday as polling stations across the country opened to the public in the morning. (Xinhua/Han Yan)