ON WEDNESDAY night, Boris Johnson told the crowd gathered for the Spectator’s Parliamentarian of the Year Awards in London that the Government was going to make a “Titanic success of Brexit”.

It may have been a slip of the tongue from the Foreign Secretary, but yesterday, the good ship Brexit smashed head first into a giant iceberg in the shape of the High Court and parliamentary sovereignty. Investment manager Gina Miller, London-based Spanish hairdresser Deir Dos Santos and the People’s Challenge group, backed by a crowd-funding campaign, had brought a case saying Brexit without a vote in Parliament was illegal.

The Government’s lawyers had argued that the royal prerogative was a legitimate way to give effect “to the will of the people”, as dictated by the EU referendum.

The Lord Chief Justice, Lord Thomas of Cwmgiedd, disagreed: “The Government does not have power under the Crown’s prerogative to give notice pursuant to Article 50 for the UK to withdraw from the European Union.”

Three judges looked at the case, and dismissed the Government’s arguments. They said triggering Article 50 would fundamentally change the rights of people living in the UK, something the Government could not do without permission of Parliament. In effect, the judgment means the Government can’t start the process of leaving the EU without Parliament passing a law.

The Government had said it would appeal to the Supreme Court. It insisted its Brexit plans were still on track, and that Article 50 would definitely be triggered by the end of March.

But last night Theresa May conceded the logical conclusion of the ruling was that a bill would have to go in front of Parliament.

Brexit Secretary David Davis had earlier said: “The judges have laid out what we can’t do and not exactly what we can do, but we are presuming it requires an act of Parliament, therefore both Commons and Lords.”

That, May said, would be the “logical conclusion”. A formal bill will have a tricky time in Parliament, facing a full debate and amendments from pro-Remain MPs, or those opposed to a hard Brexit, that will slow it down or possibly even destabilise it all together. It will give the SNP group far more influence over the Brexit negotiations than they have had to date.

A cabinet minister will make a statement to the House of Commons on Monday.

Labour leader, Jeremy Corbyn, said: “This ruling underlines the need for the Government to bring its negotiating terms to Parliament without delay. Labour respects the decision of the British people to leave the European Union. But there must be transparency and accountability to Parliament on the terms of Brexit.”

At the Spectator Awards, as Johnson talked of a Titanic success, May put her head in her hands, and Chancellor George Osborne heckled him. “It sank,” he said.

“Well, the Titanic exhibition in Northern Ireland is the single most popular attraction in the province,” Johnson replied.

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