The UK's highest court has been told that a motion in Parliament would not have any effect on the legal issue it is having to decide over the Government's Brexit strategy.

Eleven justices at the Supreme Court in London heard the submission from the top lawyer who is opposing an appeal by the Government against a November High Court ruling blocking its plan for triggering Britain's exit from the European Union.

Lord Pannick QC was speaking on the third day of the Government's attempt to persuade the justices to overturn the High Court's decision that ministers have no power to use the royal prerogative to trigger Article 50 of the Lisbon Treaty and start the two-year process of withdrawing from the EU without the prior authority of Parliament.

During his argument on behalf of Gina Miller, the investment fund manager and philanthropist who won the historic ruling on November 3, Lord Pannick referred the justices to the fact that "a motion may be approved in the House of Commons today".

He told the panel, headed by the Supreme Court's president Lord Neuberger: "Only an Act of Parliament could lawfully confer power on the appellant to notify. Why is that? Well, because notification will nullify statutory rights and nullify a statutory scheme.

"The law of the land is not altered by a motion in Parliament. This is a basic constitutional principle."

Lord Pannick told the packed court on Wednesday: "Our submission is that a motion in Parliament can't affect the legal issues in this case. A motion in Parliament simply cannot rectify what is otherwise a legal deficiency in the appellant's case."

Earlier, he said that triggering Brexit will "frustrate or render insensible" a large number of UK laws and is a reason why Parliament must be involved in the notification process.

The June referendum which resulted in a clear majority in favour of leaving the EU was "a very important matter" but had nothing to do with the legal issue before the court, which concerned "who has the power to notify?"

Brexit Secretary David Davis is leading the Government's appeal against the High Court ruling. Prime Minister Theresa May has made it clear she still intends to give an Article 50 notification by the end of next March to start the leave negotiations with 27 other EU countries.

James Eadie QC, for the Government, has insisted that it does have the legal power to use the prerogative to trigger Britain's exit from the EU and has rejected the suggestion that its Brexit strategy was an "affront" to parliamentary sovereignty.

But, Lord Pannick has declared: "Parliament is sovereign. What Parliament created, only Parliament can take away."

He told the justices: "I invite the court not to accept any suggestion that the legal limits on ministers' powers are to be left to, or influenced by, political control - or Parliamentary control - short of an Act of Parliament."

His argument was supported by Dominic Chambers QC, appearing for London hairdresser Deir Dos Santos, who is also at the centre of the battle to block the use of the royal prerogative in Brexit without primary legislation.

Mr Chambers said that, under the doctrine of parliamentary sovereignty, "Parliament is supreme" and no other person or body could nullify or set aside legislation Parliament enacted.

The doctrine, "forged on the battlefields of 17th-century England in the clash between the Crown and Parliament", meant the Government appeal must be dismissed because it was attempting to use the royal prerogative to set aside EU law rights enshrined in domestic law by Parliament without primary legislation.

Mr Chambers added: "In the absence of such parliamentary authorisation, by triggering Article 50 the Government will be acting contrary to the doctrine of parliamentary sovereignty, and so the Government will be acting unlawfully.

"At the heart it really is as straightforward as that."