Legislation that would allow the British government to trigger what's known as Article 50 and start negotiating its exit from the European Union could be put before parliament as early as Thursday. That's after the Supreme Court ruling on Tuesday that - in essence - said parliament must be consulted beforehand. But how many MPs will vote against? Will amendments be tabled to frustrate the process? James Menendez spoke to Alison Young, Professor of Public Law at Oxford University and Rob Watson, BBC's political correspondent. First, what will the Brexit bill entail?