The referendum result itself is not legally binding in UK law, and it alone does not trigger the UK’s departure from the EU. That has to be done under the withdrawal process laid down in Article 50 of the Lisbon Treaty.
Constitutional lawyers are now clearly arguing that the Prime Minister is not able to issue a declaration under Article 50 of the Lisbon Treaty – triggering our withdrawal from the European Union – without having been first authorised to do so by an Act of the United Kingdom Parliament.
A law firm is now taking action to ensure the formal process for the UK leaving the EU is not started without an act of Parliament.
Lawyers Mishcon de Reya, said it would be unlawful for a prime minister to trigger Article 50 without a full debate and vote in Parliament.
Writing in the Times and cited by the BBC the crossbench peer Lord Pannick QC, a specialist in public law, said: “Whether Parliament would enact legislation to allow for an Article 50 withdrawal is a matter for it. However, without such legislation, the prime minister cannot lawfully give a notification.”
Similar views have been expressed by Lord Lester QC and Sir Malcolm Jack, a former clerk to the House of Commons.
A here.public law case has also been crowdfunded