(FILES) In this file photo taken on January 23, 2013 British Prime Minister David Cameron delivers a speech on 'the future of the European Union and Britain's role within it', in central London, on January 23, 2013. - 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 BEN STANSALL / AFP)