The UK Government faces a wait until next year to find out whether it has won its Brexit challenge at the UK's highest court.
At the completion of four days of detailed legal argument, 11 Supreme Court justices reserved their ruling until the new year.
The QC representing Government-challenger Gina Miller at the Supreme Court's Brexit hearing has said the 1972 Act, which took the UK into Europe, does not allow for it to be overridden by prerogative power.
Lord Pannick QC told the court that ministers had no power to "nullify" the 1972 Act after it was enacted and take away statutory rights and obligations created under it "without parliamentary approval".
He said: "There is no relevant prerogative power in this context."
Lord Pannick said the question was whether Parliament had intended by later legislation to confer a new power to that effect.
"I say only the clearest of statements by Parliament to that effect could create a new prerogative power.
"I say post-1972 legislation is very far from containing any such clear statement."
ITV News reporter Olivia Kinsley is watching the court proceedings.
Gripping TV it may not have been but the televised four-day hearing was a box office event for fans of legal argument.
The UK's highest court has been told that a motion in Parliament does not have any bearing on the legal issue it is having to decide.
The Supreme Court is hearing an appeal to overturn a High Court ruling that said the prime minister could not trigger Article 50.