London law firm Mishcon de Reya said it had started legal action, demanding that the British government win legislative approval from Parliament before triggering a formal divorce from the European Union.
Mishcon de Reya, a leading London-based firm, said a British leader would need an Act of Parliament before invoking Article 50 of the Lisbon Treaty, the trigger for formal negotiations on exiting the bloc Britain joined in 1973.
The action is the first concrete signal since the June 23 referendum that the implementation of the 52-48 Brexit vote could be challenged, or at least amended.
Because the referendum is not legally binding, some lawmakers and campaigners have suggested that Parliament review the vote, call a second referendum or at least that Article 50 be voted on by Parliament to ensure Britain gets the right deal.
The law firm said in a statement that its clients were a group of concerned British citizens, but it did not name them or say who was paying for the suit.
“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,”c, a partner Mishcon de Reya, said in the statement.
Mr Nouroozi said the government must 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.”
Firm spokeswoman refused to give names of those backing the action, though property website Zoopla said its CEO Alex Chesterman was a supporter.
The Brexit vote unleashed panic in foreign currency markets, pushing sterling to a 31-year-low, and prompted the worst political crisis in modern British history with both main parties in turmoil.
All five Conservative Party candidates running to replace Prime Minister David Cameron say Britain will leave the EU and say the negotiation will hinge on the balance between limits on immigration and access to the European Single Market.
Mr Cameron has said the decision on triggering Article 50, 250-words in the Lisbon Treaty, is for the next PM.
