The Supreme Court ruling explained: The government requires primary legislation before it can change the constitution

The Supreme Court’s ruling against the government is measured and restrained in tone – but it is the most important constitutional case the Court has ever heard, writes Jo Murkens. The Justices have ruled that the government cannot leave the EU without Parliament’s consent. And while they also declared EU membership a reserved matter and therefore one that must be decided at Westminster rather than by devolved institutions, this is unlikely to be the end of the story.