The high court is to decide whether government or parliament has the authority to trigger exit process. We look at what a pro-parliament verdict could mean

What is happening in the article 50 court case?

Judgment is awaited on whether parliament or the government has authority to give formal notification under article 50 of the Treaty on the European Union of the UK’s intention to leave the EU. The government claims it is entitled to do so under the executive powers it has inherited from the crown under the royal prerogative.

How does this tie in with the article 50 case in Belfast?



A similar claim, which additionally stressed devolution law, has already been heard in the high court in Belfast. The 1998 Good Friday Agreement prevents Brexit being imposed on the people of Northern Ireland, Ronan Lavery QC told the court earlier this month. The former Northern Ireland justice minister, David Ford, nationalist and Green politicians have brought the claim. Judgment in that case is also awaited. Both claims, whichever way they go, are expected to be appealed directly to the UK’s supreme court in Westminster. A hearing, probably in front of at least nine justices, has been pencilled in for early December.

Who has brought the cases?



While attention has focused on the lead claimant in London, 51-year-old Gina Miller, a Guyanese-born and British-educated businesswoman, there are scores of other litigants and interveners. The second lead claimant there is Deir Dos Santos, a London hairdresser. Both Miller and Dos Santos are British citizens. Others funding the challenge include people living in England, Wales and Northern Ireland, British expatriates living in the EU, Gibraltarians worried about the future status of the Rock and the children of non-EU nationals. All worry that Brexit may deprive them of existing rights. Death threats have been made against claimants, prompting the judges to warn that those interfering with the case could be imprisoned for contempt of court.

Article 50 legal case 'is attempt to reverse Brexit', court told Read more

If they win, could this stop Brexit?



Victory for the claimants would hand responsibility for triggering Brexit to MPs. Whether a majority would have the nerve to delay or defy the referendum result is unknown. Many, though personally committed remainers, may feel bound by the popular plebiscite. Other politicians might respect constituency pressures. Both the Scottish and Welsh devolved governments retained barristers on a watching brief at the London hearing. They could join the case at the supreme court, reinforcing legal opposition to Theresa May’s executive action.

How worried is the government?



It is difficult to predict the outcome of a case. The attorney general, Jeremy Wright QC, the government’s most senior legal adviser, led its team of lawyers in London to demonstrate political commitment to Brexit. The judges hearing the case include the Lord Chief Justice, Lord Thomas of Cwmgiedd, who at one point in the three-day hearing admitted that he was “slightly baffled” by government lawyers’ arguments. Sir Terence Etherton, the new Master of the Rolls, asked whether the fact that parliament had not specified the precise limits of the royal prerogative meant that “the government can remove common law rights?” The claimants have exploited the Bill of Rights 1689, a piece of legislation revered by Eurosceptics, pointing out that it “expressly prohibits the use of the prerogative in circumstances where its exercise would ‘suspend’ or ‘dispense’ statutory law”. The outcome is hanging in the balance.

If it goes to the supreme court, then what?



Technically, there could be an appeal to the European Court of Justice in Luxembourg, the EU’s highest court, on a point of law. No one, however, wants the EU to decide on the limits of parliamentary sovereignty. If the supreme court rules against the government, parliament is likely to be given a vote on when, and possibly how, to trigger Brexit.

Who’s paying?



Miller, who is an investment manager, has been funding her claim. Much of the additional cash has come from various crowdfunding websites.