03/11/2016 13:15 GMT | Updated 04/11/2017 05:12 GMT

Brexit Itself Cannot Be Disputed - But It Is Right That Parliament Has A Say In How Britain Leaves The EU

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The High Court's judgment earlier today was a positive step. But our country needs much more than just a symbolic act. This decision should not be seen in isolation, as a mere opportunity for a brief, high-profile vote on triggering Article 50. We need to use this opportunity to give the British people, and their elected representatives in Parliament, real input in the Government's negotiating aims. Before Article 50 is triggered, we need to know what Brexit is to mean.

It was always wrong for the Government to try to stop Parliament having a meaningful say in how the UK leaves the EU. Leave campaigners fought - or said they fought - for parliamentary sovereignty. In this context, their anger at the court's decision is truly baffling to see.

But they should not fear. There is a mandate to leave the EU - even a passionate Remainer like me can see that and respect it. However, there is no mandate for a hard, destructive Brexit. Leaving the European Union was on the ballot paper. Leaving the Single Market, the Customs Union, Europol, the European Arrest Warrant, the Erasmus programme and so on was not on the ballot paper. The fact of Brexit cannot be disputed, but it is right that its form should be the subject of parliamentary approval and vigorous public and political debate.

Those Leave campaigners who want a hard Brexit should be confident enough in their case to see it subjected to parliamentary scrutiny. Then we can have the debate the British people need about whether to cut our country off completely from Europe, or whether to go for a Brexit deal that keeps us open and maintains some of the best aspects of our EU membership. If this ruling means anything, it means that the meaningless mantra of 'Brexit means Brexit' has to come to an end. The Government must now start to publicly set out what it is they want as they enter negotiations with our European partners.

That is why Open Britain is calling on the Government to bring forward their substantive plans for the negotiations - in the equivalent of a White Paper - to be debated and voted on in Parliament before Article 50 is triggered.

This is not, as some of the more hysterical commentators have said, about 'blocking Brexit'. Nothing could be further from the truth. Like everyone in the Open Britain campaign, I accept the verdict of the people, and now we need to make the best of it. But Leave campaigners who reject the idea of even discussing the form that Brexit takes are running scared of democracy.

Everyone who believes in keeping Britain an open country - open to business, to talent, to Europe and the world - should welcome the Court's decision. Now we need to focus on fighting for a Brexit deal that will retain our openness and prosperity in the years to come.