Speed Reads

Brexit interrupted

Britain's High Court throws a wrench in Brexit plans

On Thursday, Britain's High Court ruled that Prime Minister Theresa May doesn't have the power to trigger Britain's withdrawal from the European Union, as she planned to do by March 31, 2017. Instead, the court ruled, Parliament must approve the activation of Article 50 of the E.U. charter, which allows a country to withdraw from the union "in accordance with its own constitutional requirements." May argued that the prime minister can use the royal prerogative to withdraw, after Britons narrowly voted to leave last summer, but the senior judges disagreed, ruling that "the government does not have the power under the Crown's prerogative" to start Brexit talks.

The government is expected to appeal the ruling, the most important constitutional challenge in decades. The royal prerogative, originally and officially held by the Queen, is used by British prime ministers to negotiate treaties, declare war, and do more mundane things like issue passports without votes in Parliament. Using those powers to strip rights from U.K. citizens, as leaving the E.U. would, impinges on Parliament's sovereignty, said the chief justice Lord Thomas of Cwmgiedd, and "the most fundamental rule of the U.K. constitution is that Parliament is sovereign." The Supreme Court has set aside room for an appeal next month.