(FILES) In this file photo taken on April 15, 2016 London Mayor and Conservative MP for Uxbridge and South Ruislip, Boris Johnson addresses campaigners during a rally for the "Vote Leave" campaign, the official 'Leave' campaign organisation for the forthcoming EU referendum, in Manchester, northern England, on April 15, 2016. - Severing a truculent partnership stretching back five decades, Britain finally went its own way late Thursday four-and-a-half years after its shock referendum verdict in favour of divorcing the EU. Brexit became reality as Big Ben struck 11:00 pm (2300 GMT) in central London, just as most of the European mainland ushered in 2021 at midnight. (Photo by OLI SCARFF / AFP)