In the judgement that they delivered in the High Court on 3rd November 2016, the judges say (§111, page 32) that the Government does not have the power to give notice under Article 50 of the EU Treaty. Their exact words are:
“For the reasons we have set
out, we hold that the Secretary of State does not have power under the Crown’s
prerogative to give notice pursuant to Article 50 of the TEU for the
Their words were chosen to reflect the nature of the complaint that was made to the Court: the Government was represented in this matter by the Secretary of State for Exiting the European, and the act complained against was giving notice. The complaint was against giving notice rather than against deciding to withdraw because giving notice is a particular and definite act, whereas deciding is difficult to pin down in that way – the Government does not make decisions in a formal way, by a vote for example.
The judges make it clear, however, (§§15/16, page 5) that there is no real difference, and that the Government does not have the power to decide any more than it has the power to give notice. Paragraph 16 says:
“The notification under Article
50(2) is of a decision under Article 50(1).
If the Crown has no prerogative power under the constitutional law of
Apart from its prerogative powers, the only powers the Government has are those given to it by Act of Parliament. The EU Referendum Act 2015 definitely did not give it any powers. The only way it can get the power to give notice under Article 50(2) is for Parliament to pass an Act that gives it that power, by making the decision required by Article 50(1) – a decision to Leave the EU. Only Parliament can decide.