Parliamentary consent needed to trigger Article 50, says HoL

Bypassing Parliament would set a “disturbing precedent” for the government if it acted on the Brexit result from the European Union referendum in June, without explicit consent from Britain’s legislative body, the report said.

The upper chamber said Parliament should play a central role in the decision to trigger Article 50 - the two year formal negotiation process of Brexit from the Lisbon Treaty - and have a key role in scrutinising talks with the EU and the final deal.

The report said: “In our representative democracy, it is constitutionally appropriate that parliament should take the decision to act following the referendum. This means that parliament should play a central role in the decision to trigger the Article 50 process, in the subsequent negotiation process, and in approving or otherwise the final terms under which the UK leaves the EU.

“It would be constitutionally inappropriate, not to mention setting a disturbing precedent, for the executive to act on an advisory referendum without explicit parliamentary approval – particularly one with such significant long-term consequences. The government should not trigger article 50 without consulting parliament.”

Article 50 says,“any member state may decide to withdraw from the union in accordance with its own constitutional requirements", but it is ambiguous about what the constructional requirements actually are.

Lord Lang of Monkton, the committee chair, said parliamentary assent could be sought by legislation or through resolutions in both Houses of Parliament.

He said: “An Act of Parliament would give greater legal certainty and could be used to enshrine the ‘constitutional requirements’ required by Article 50, allowing for the setting of advantageous pre-conditions regarding the exit negotiations to be met before Article 50 could be triggered.

“A resolution could be simpler and quicker to secure but might not provide the same watertight legal authority. We consider that either would be a constitutionally acceptable means of securing parliamentary approval for the triggering of Article 50.”

The report said it was unclear whether once it is triggered, if it could be reversed by Britain, so the government should activate the clause "only when it is in the UK's best interests to begin the formal two-year negotiation process".

In October, the government is facing a legal challenge over whether it and the Prime Minister can use its executive powers to invoke Article 50.

Theresa May said she would not trigger Article 50 this year, but she is facing pressure from the pro-Brexit contingent of her party to activate the clause early in 2017, before general elections are held in France and Germany in the spring and summer.