A case brought last year argues the government cannot leave the Single Market without triggering Article 127 of the European Economic Area agreement – and says it must seek approval from MPs to do so. The hearing will decide whether or not the case carries enough clout to go to a full trial.
It was initially brought by chair of pressure group British Influence Peter Wilding and lobbyist Adrian Yalland.
The merit hearing was due to take place this week. However, City A.M. understands this has been postponed until early February.
Meanwhile, the government's legal eagles are still bracing themselves for the outcome of their Article 50 appeal, which was heard by all 11 of the Supreme Court justices in early December, after a trio of High Court judges decided the government must get the thumbs up from MPs before it can trigger Article 50.
No official date for the hand down of the judgment has been given, but it is widely believed to be due some time this month. The country's top court has told those who have enquired that it will aim to give at least three working days' notice before the judgment is due.
However, that timeframe means the final decision will more than likely not be known by the time Prime Minister Theresa May gives her much anticipated Brexit speech on Tuesday. The Supreme Court has also stated it is not handing out any advance copies of the judgment.
The initial Article 50 case was heard in the High Court in October last year, with the decision delivered in November. Although it was brought to the court by a number of interested parties, businesswoman Gina Miller was selected as lead claimant.