Article 50 lawsuit seeks parliament vote before Brexit

Several lawsuits have been filled in a single claim asking the Supreme Court to rule that the Prime Minister needs to seek approval of parliament before invoking Article 50, the two-year process to leave the European Union.

Claimants include a hairdresser and an investment entrepreneur, who bought the case to law firm Mishcon de Reya, who want Theresa May to obtain and act of parliament before initiating Article 50 of the Lisbon treaty. They claim that to not do so would be unlawful.

Most MPs campaigned to remain in the EU and a parliamentary vote would force them to choose between ensuring economic stability by placating financial markets or carrying out the will of the electorate.

The case is likely to be bought to the Supreme Court by the end of this year. May previously said she would not activate Article 50 until 2017.

“This will be one of the most important constitutional law cases ever decided," University College London law professor Jeff King told Bloomberg.

According to lawyers and judges interviewed, the case could put the power of the judiciary against the authority of the Prime Minister and the government.

At a hearing on 19 July, the claimants were identified as entrepreneur Gina Miller, co-founder of investment group SCM Direct, and hairdresser Deir dos Santos were the only claimants identified, with others said to be put off by racist and anti-semitic abuse.

At the hearing Lord Justice Brian Leveson, renowned for his inquiry into the newspaper phone hacking scandal, said the case will be taken “very seriously”.

He said “the court takes this litigation very seriously and will move expeditiously" and said as it was "of such constitutional importance it is difficult to see why" it would not move quickly to the supreme court after a two-day hearing on 15 October.

It is possible that the court could say the government could invoke Article 50 with or without a vote in parliament. The lawsuit could also delay the decision while legal challenges play out and risk jail time for government ministers who ignore the court’s decision. Parliament could also vote for Brexit anyway, even if claimants win.

The British constitution is not written down, unlike the US, instead it was developed over the centuries from laws, customs and judicial rulings, which is one of the reasons why some lawyers have suggested it is a crucial matter of constitutional law for the PM to first gain authority from Parliament before enacting Article 50.

The case heightens uncertainty surrounding the referendum result as it was not legally binding, but politically charged.