A no-confidence vote against Theresa May by members of her own Conservative party was triggered by 48 letters from MPS – the requisite 15 percent – that were submitted to the 1922 Committee. This group opposes the Brexit deal she negotiated with the EU. The ballot takes places on Wednesday between 6pm and 8pm local time (8-10 pm in Israel). May needs the backing of at least 158 Tory MPs out of 315 to survive as prime minister and party leader and contest the broad challenge to the Brexit deal. She could decide to step down if votes against her were below the threshold to topple her, but significant enough in number. Even if she decides to tough it out, her government still faces another challenge, no confidence in Parliament. Her almost-certain departure would plunge the Brexit process into chaos.