NEW: Sky sources - Government would not need Act of Parliament to revoke Article 50, law advisers have told ministers is the consequence of ECJ ruling - “might be needed politically, but not legally" - Minister. news.sky.com/story/governme…
* if ECJ opinion from yesterday becomes a ruling in fortnight. Obv would need a fundamental change in policy from this Govt or another one. But if legal advice right, it opens up path for Parliament to give its view (say in meaningful vote amendment) and then Govt to withdraw A50
NB. would be somewhat controversial - but basic point is dont presume that because of @thatginamiller case at Supreme Court on Article 50 demanded statute, an Act of Parliament, that the reverse is legally necessary for hypothetical revocation, which, frankly, is what i presumed
As it was explained to me, the short European Union (Notification of Withdrawal Act) 2017 gives power to a sitting PM to notify, Therefore the power legally rests with the executive. That interpretation might be challenged. All rather hypothetical - but also rather interesting 
