A full act of parliament – rather than merely a motion – would be required to give ministers authorisation to trigger Brexit, the supreme court has been told.
Concluding his arguments to the court, Lord Pannick QC, who represents the lead claimant, Gina Miller, said legislation by both houses of parliament would be needed before the government could formally give notification of the UK’s intention to leave the European Union.
“Only an act of parliament can lawfully confer power on the [government] to give notification under article 50 [of the treaty on European Union],” Pannick said. “The law is not altered by a motion in parliament. A motion in parliament cannot effect the legal issue in this case.”
On Tuesday the government’s QC, James Eadie, had indicated that any bill put before parliament would only contain a “one-line” statement.
Pannick ran into stronger judicial resistance on Wednesday when he began to assess the legal significance of the 2015 referendum legislation in terms of whether it gave the government new powers.
“It would be a bit surprising if the referendum act and the referendum had no effect in law,” Lord Neuberger, the president of the supreme court, suggested. The act may have been enough for the government to say it had ceded power to the people, he added.
But Pannick replied: “The 2015 act is entirely neutral on the issue before this court: whether or not a minister has the power to notify [Brussels that the UK intends to leave the EU].”
Dominic Chambers QC, who represents Deir Dos Santos, the second main claimant, told the court’s 11 justices that if Theresa May triggered Brexit without proper parliamentary approval she would be acting “unlawfully”.
“Parliament is supreme,” Chambers said. “No person or body can override or nullify legislation. These EU law rights [acquired through the 1972 European Communities Act] are enshrined in parliamentary legislation.
“By triggering article 50 these statutory rights will be nullified and overridden. The absence of parliamentary authorisation for the executive to override primary legislation ... will be contrary to the doctrine of parliamentary sovereignty and therefore it will be acting unlawfully.”
Chambers said that the doctrine of parliamentary sovereignty was “forged on the battlefields of the 17th century in the [English civil war] between crown and parliament”.
Parliament’s victory and sovereignty was finally enacted in the bill of rights which, Chambers reminded the justices, declared that “suspension of [parliamentary] powers without authority is illegal”.
The hearing continues.
