The SNP will be allowed to make written submissions in a case designed to ascertain if Holyrood could legislate for another independence referendum.

The party sought to intervene in the case before the UK Supreme Court, which resulted from a referral by Lord Advocate Dorothy Bain QC, last month.

On Wednesday, the Supreme Court announced that the SNP’s representatives would be able to make a submission of no more than 20 pages, provided they do not repeat the Lord Advocate’s arguments.

The submission must be filed by September 21 and the Lord Advocate and Advocate General for Scotland – representing the interests of the UK Government in the case – will have two weeks to respond.

Oral arguments in the case are due to be heard on October 11 and 12, but a date for a final decision has not yet been announced.

The Lord Advocate referred a prospective independence referendum Bill to the Court in July, with her argument leaning heavily on the fact that any referendum would not be self-executing, but merely “consultative”.

This means that, in the event of a majority of Scots saying they would want to leave the union, Scotland would not immediately become independent, but the referendum could serve as the basis for independence negotiations.