Law firm Mishcon de Reya launches Brexit challenge

The firm, which has offices in London and New York, argued that while the referendum was an exercise to obtain the views of UK citizens, the majority of whom expressed a desire to leave the EU, the decision to trigger Article 50 of the Treaty of the European Union – the legal process for withdrawal – rests with the representatives of the people under the UK Constitution.

Mishcon de Reya said it has been in correspondence with government lawyers since 27 June on behalf of its clients to seek assurances it will uphold the UK constitution and protect the sovereignty of Parliament in invoking Article 50.

The law firm said that if the correct constitutional process of parliamentary scrutiny and approval is not followed, the notice to withdraw from the EU would be unlawful, denting withdrawal negotiations and the UK’s future political and economic relationships with the EU.

Partner Kasra Nouroozi said: “We must ensure that the government follows the correct process to have legal certainty and protect the UK Constitution and the sovereignty of Parliament in these unprecedented circumstances. The result of the referendum is not in doubt, but we need a process that follows UK law to enact it. The outcome of the referendum itself is not legally binding and for the current or future Prime Minister to invoke Article 50 without the approval of Parliament is unlawful.

"We must make sure this is done properly for the benefit of all UK citizens. Article 50 simply cannot be invoked without a full debate and vote in Parliament. Everyone in Britain needs the government to apply the correct constitutional process and allow Parliament to fulfil its democratic duty which is to take into account the results of the referendum along with other factors and make the ultimate decision.”

Mishcon has retained Baron David Pannick QC and Tom Hickman to act as counsel in this action, along with Rhodri Thompson QC and Anneli Howard.