The Supreme Court has begun a landmark legal hearing into whether Parliament’s consent is required before official Brexit negotiations can begin. Its 11 justices will hear a government appeal against last month’s High Court ruling that only Parliament has the authority to trigger Article 50. The hearing, being streamed live by the BBC, is expected to last four days, with the verdict expected in January. The outcome will have implications for Theresa May’s strategy for EU exit. But it is not a court case on whether or not Brexit actually takes place.