BRUSSELS, BELGIUM - OCTOBER 20:  President of the European Council Donald Tusk addresses assembled media as he arrives at the Council of the European Union on the first day of a two day summit on October 20, 2016 in Brussels, Belgium. Theresa May is attending her first EU Council meeting as the British Prime Minister. The government's Brexit strategy continues to be debated in the UK with Article 50 of the Lisbon treaty to be triggered by the end of March 2017.  Article 50 notifies the EU of a member state's withdrawal and the EU is then obliged to negotiate a withdrawal agreement. The process will take two years seeing the UK finally withdraw from the Union in March 2019. (Photo by Jack Taylor/Getty Images)