Judges at the High Court in London have rejected the latest legal challenge brought over the Prime Minister Boris Johnson's decision to suspend parliament for five weeks.
An appeal's now being launched against the ruling at the Supreme Court.
Campaigners say they expect that hearing to be held on 17th September.
Speaking outside court, Gina Miller - who launched the legal bid - said: "As our politics becomes ever more chaotic, we feel it is absolutely vital that parliament should be sitting.
"We are therefore pleased that the judges have given us permission to appeal to the Supreme Court - which we will be doing."
She added: "My legal team and I will not give up the fight for democracy."
A court in Scotland had previously ruled that Boris Johnson's decision is lawful, rejecting a bid by a group of 70 MPs to secure a temporary injunction blocking the bid.
That case is also being appealed.
