John Bercow, speaker of the House of Commons, left, arrives to attend a service to mark the centenary of the Armistice at St Margaret’s Church, Westminster Abbey in London, U.K. (Photographer: Chris Ratcliffe/Bloomberg)

Meet May's Brexit Nemesis: U.K. Parliament Speaker John Bercow

(Bloomberg) -- In the long history of British politics, the role of the Speaker in Parliament has at times been perilous: Between 1394 and 1535 seven holders of the office were executed by beheading.