The Government and Respondents both made their arguments before the Supreme Court today; with both sides asserting that their position is the constitutionally conventional one (i.e. that it respects the sovereignty of Parliament).
The Government argued that the Respondents are seeking to set a "constitutional trap"; asking the Supreme Court to find that Parliament intended to remove the Government's prerogative power (to withdraw from the EU) the moment the UK joined. Parliament intended no such thing and, what is more, Parliament has never decided to restrict the Government's prerogative powers in respect of triggering Article 50, despite having ample opportunity to do so. The silence in the European Union Referendum Act 2015 is further evidence that Parliament intended that the Government should start the process of leaving the EU.
This afternoon, the Claimants have begun to argue, to the contrary, that Parliament knew exactly what it was signing up for when it passed the legislation giving effect to the UK joining the EU. Parliament's decision to incorporate EU law in domestic UK law has created domestic rights for UK citizens that only Parliament can now take away. The silence in the European Union Referendum Act 2015 is further evidence that Parliament intended that only it is entitled to unravel this constitutional framework.
The irony is that this highly politicised legal debate has fallen to be resolved by the Court, mere metres away from where the legislation itself was passed and where Parliament could have answered these questions, if it had not remained silent on the matter.
Read the transcript of this afternoon's session here.