The government’s Brexit stance is riddled with legal confusion

There has never been a more vacuous phrase than “Brexit means Brexit,” or less clarity about what on earth it will mean as Britain stumbles to the door. In particular, there is still no practicable solution to the Irish border issue, because inconsistent assurances have been given to European Union negotiators and the various UK ideological tribes.

The phase one transition agreement says that in the absence of another acceptable solution for keeping an open Irish border, the backstop is that Northern Ireland will “align” with EU trade rules. The DUP has been promised that there will be no customs border down the Irish Sea either: one rule for the whole UK. The Brexiteers have been promised that there will be no customs union between the UK and the EU. These are three mutually inconsistent promises as to what Brexit means. And both the Treasury and the Bank of England project that whichever version of Brexit we adopt any will make the UK far worse off.

Yet some perverse version of Dunkirk spirit seems to persuade many people, even those who never wanted to leave the EU, that what’s done is done; the only question being how bravely we manage the withdrawal.

This is not true. In debating what might happen next, it is vital to remember what is still legally possible. It is politically, as well as constitutionally important to understand that the deed is not yet done. We are not yet tied to leaving the EU; and in fact the prime minister does not yet have power to take us out. If parliament votes against the terms of whatever deal the prime minister can obtain, then the default fallback position is not that we crash out of the EU, but that we remain in.

After the EU referendum, in the Miller case, the Supreme Court reasserted the basic constitutional principle that it was for parliament, not the prime minister, to decide whether to repeal all EU law by leaving the EU.

The judgment was long and complex, but—in a nutshell—an advisory referendum is not a source of law. It was parliament which took us into the EU, and made its law part of UK law, by passing the European Communities Act 1972. So only parliament had the authority, by passing legislation, to stop EU law applying directly in the UK.

The consequence of the Miller case was that the prime minister had to get an act of parliament before she could trigger Article 50 and give notice to leave the EU. She got one fast. The EU (Notification of Withdrawal) Bill was introduced just two days after the Supreme Court judgment in Miller, became law on 16th February 2017, and the prime minister formally notified the European Council of the UK’s intention to withdraw from the EU on 29th March 2017.

So far so constitutional. But the EU (Notification of Withdrawal) Act, passed so hastily, only gave the prime minister power to give notice of her current intention to withdraw the UK from the European Union. It did not provide any power actually to leave, and the government defeated a Labour amendment to say what would happen if acceptable terms were not reached. Despite warnings from cross-bench peers, including David Pannick (who argued the Miller case), John Kerr (who drafted Article 50), and David Hope (former Vice-President of the Supreme Court), the government refused to amend the Bill, and the Act passed without any provision as to how and when parliament would give permission for the deal (or no-deal) Brexit actually to take place.

Britain’s constitutional arrangements require parliamentary authority not only to notify an intention to leave the EU, but also actually to leave. The latter has not yet been conferred. It will be granted, if it is passed, by the European Union (Withdrawal) Bill, currently going through parliament. But this Bill was amended after an unlikely rebellion led by former Attorney General Dominic Grieve MP, to mean that parliament does have a vote on the “final deal” with the EU before it is signed.

What happens if, as a result of that vote, parliament rejects whatever deal is on offer? The government says the only other option is to leave with no deal. That is simply constitutionally wrong. In the absence of parliamentary authority, the prime minister cannot take us out of the EU on any terms at all. That is what the rule of law means.

Were the government to attempt to take us out of the EU without a deal approved by parliament, it is likely that this would be subject to a further successful court challenge. As Hope put it, “It is all about respecting the sovereignty of parliament.  The law will see to that, whatever the government think, as it always does.”