Parliament alone has the power to trigger Brexit by notifying Brussels of the UK’s intention to leave the European Union, the high court has ruled.

The judgment (pdf), delivered by the lord chief justice, Lord Thomas of Cwmgiedd, is likely to slow the pace of Britain’s departure from the EU and is a huge setback for Theresa May, who had insisted the government alone would decide when to trigger the process.

The lord chief justice said that “the most fundamental rule of the UK constitution is that parliament is sovereign”.

A government spokesman said that ministers would appeal to the supreme court against the decision. The hearing will take place on 7-8 December.

More at The Guardian.