Professor Sionaidh Douglas-Scott, Anniversary Chair in Law and Co-Director at the Centre for Law and Society in a Global Context (CLSGC) at Queen Mary University of London (QMUL), assesses why the government has been told that it cannot use the royal prerogative to trigger Brexit in The Observer. “The June referendum resulted in a vote for the UK to leave the EU. However, it did not determine the way in which the UK leaves the EU. The court’s judgment means that the elected parliament will have a role in debating and deciding many matters, rather than their being determined in private by the executive,” she writes.