A pro-remain protester holds up an EU flag with one of the stars symbolically cut out in front of the Houses of Parliament shortly after British Prime Minister Theresa May announced to the House of Commons that Article 50 had been triggered in London on March 29, 2017. - Prime Minister Theresa May today said there could be "no turning back" and called for national unity, after notifying the EU of Britain's intention to end its 44-year membership of the bloc. (Photo by OLI SCARFF / AFP)        (Photo credit should read OLI SCARFF/AFP/Getty Images)