Supreme Court Brexit ruling: Dr Mike Finn, Researcher in British Politics (Expert in UK Politics)

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Published historian of the UK constitution and a former Head of Research and political speechwriter in the Lib Dem Leader's Office under Charles Kennedy and Sir Menzies Campbell. He was also Kennedy's Principal Policy Adviser when he was in the parliamentary assembly of the Council of Europe and when he was President of the European Movement.

His round-up from the last hearing,

“The court appeared sceptical of a number of premises of the government's argument - though James Eadie, the government's counsel, did well overall, in the afternoon session he was pushed on a number of issues, not least the question of of whether Parliament and the Executive had engaged in a joint venture in joining the EU (then the EEC) in the first place. Eadie had to concede they had, but that this process shouldn't be replicated for withdrawal. Eadie spent a considerable amount of time attempting to unpick the European Communities Act, but was pushed on why he was so focused on that when the ratification of Lisbon had superseded it.

Eadie is in a difficult position. His tub-thumping finale - invoking the spectre of the 'man on the street' - will play to the gallery but I suspect not to the justices. They had already pointed out that if the man on the street didn't get the finer points of law, they could always ask a lawyer. At times, Eadie appeared to be arguing that Parliament was redundant and the prerogative had the power to quash most if not all rights. In turn, his invocation of the man on the street also seemed to imply the legal profession and the judiciary were redundant.

His strongest arguments were around what the referendum was initially supposed to mean, and the government's pledge to honour it. That led him into a point whereby he could argue that Parliament had already, in effect, legislated to endorse Article 50 as the intention of the executive to honour the referendum result had always been clear. It's also become a modern constitutional convention that the executive honours referendum results.

There's a certain amount of misdirection in Eadie's line of attack. No-one is questioning the validity of the Royal Prerogative, ancient or otherwise. What's being question is whether it applies - whether it is sufficient - in this case. The Royal Prerogative has been consistently been limited by Parliamentary legislation, and even the rise of new conventions. Until the Iraq War, it was unusual for British Prime Ministers to ask Parliament for a vote to authorise military force. Now, it it is a standard process. This has effectively limited that prerogative power.

Thus far there has been little presented which appears to invalidate the High Court's original decision.

No-one seriously believes Parliament would invalidate Brexit - that would cause a constitutional crisis. But the shrill tone of some Brexiteers (such as IDS) arguing that the Court could cause one is misplaced and misguided. The court has no interest in Brexit as an issue, it has an interest in ensuring the government does not exceed its legal powers.”

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