20.On 4 May 2016, before the referendum, we published our report on The process of withdrawing from the European Union13. We concluded that, in the event of a Member State deciding to leave the EU, “the process described in Article 50 is the only way of doing so consistent with EU and international law”. That conclusion is now generally accepted.
21.The scope of Article 50 is limited to withdrawal itself—the process of legal separation between the EU and the withdrawing Member State. The only reference to wider considerations is a requirement that the Union, in concluding a withdrawal agreement, should “[take] account of the framework for [the withdrawing state’s] future relationship with the Union”. There is a two-year deadline for the negotiations, at the end of which the withdrawing Member State will cease to be bound by the EU Treaties, unless the European Council unanimously agrees to extend the deadline.
22.The steps that the United Kingdom must take to complete its withdrawal from the EU can thus be broken down into four distinct phases:14
23.While these stages may be logically distinct, their precise sequencing is unclear, and in practice they may overlap. In the following chapters we describe the stages in more detail, and identify, for each stage, the key points at which decisions will be sought from Parliament, as well as the opportunities for, and obstacles to, parliamentary scrutiny more broadly. We focus in particular on the second phase, the negotiations themselves—the phase in which, as we described in Chapter 2, the arrangements for parliamentary scrutiny are least clear, and during which Select Committees could potentially play a key role.
13 European Union Committee, The process of withdrawing from the European Union (11th Report of Session 2015–16, HL Paper 138)
14 House of Lords Library, Leaving the EU: Parliament’s Role in the Process, Library Note, LLN 2016/034, July 2016, which, although using different terminology, identifies four substantially similar phases.