The court agreed with the UK government, according to which the only way to hold a legal referendum on independence is by means of striking a deal between the London and Edinburgh executives, as was done in 2012 with the signing of an agreement between David Cameron and Alex Salmond.
Besides the UK legal system, the judges have also referred to self-determination. The Scottish National Party (SNP) argued that the right to self-determination is fundamental and inalienable in international law and that it applied in this case. The Supreme Court has rejected this by reference to the Supreme Court of Canada’s 1998 opinion 2 S.C.R. 217 in relation to Quebec. According to that opinion, “the right to external self-determination” —i.e. secession— only applies “a right to external self-determination in situations of former colonies; where a people is oppressed, as for example under foreign military occupation; or where a definable group is denied meaningful access to government to pursue their political, economic, social and cultural development.” “None” of these contexts “applies to Scotland,” the UK Supreme Court said.
Following the Supreme Court's decision, Scotland’s First Minister Nicola Sturgeon said that only “one route to Scotland’s being heard on independence” had been blocked. “In a democracy,” she went on, “our voice cannot and will not be silenced.”
Sturgeon had previously said that, if the Supreme Court rejected the possibility of a unilateral referendum, she would seek to turn the next UK general election into “a de facto plebiscite.” Unionist parties reject this notion.