Hampstead and Kilburn MP Tulip Siddiq has said she is willing to leave the shadow cabinet to vote against Brexit following the Supreme Court decision today that the matter must be put before Parliament. Prime Minister Theresa May said she is committed to ensuring the UK leaves the EU’s single market Picture: Jonathan Brady/PA Images She joined Hornsey and Wood Green’s Catherine West and Holborn and St Pancras’s Keir Starmer in lauding the court’s judgement that Prime Minister Theresa May cannot begin exit talks with the EU until MPs and peers have assented.