SNP MPs could introduce a private member’s bill at Westminster to hold a second independence referendum in Scotland, according to two leading academics.

Chris McCorkindale and Aileen McHarg argued the move could put political pressure on the UK Government, however it would almost certainly not get passed.

Writing for the UK Constitutional Law Association (UKCLA), the pair assessed the options for Nicola Sturgeon and the SNP if the Prime Minister fails to hand independence referendum powers to the Scottish Government, as requested by the First Minister.

“What can [the Scottish Government] do proactively to advance its position? Strategically, it is likely that the Scottish Government has always anticipated that the UK Government will reject its call for a referendum in 2020.

“Instead, there seems to be an attempt to frame any such rejection – and the democratic case more broadly – as the central issue of the 2021 election to the Scottish Parliament.”

READ MORE: AUOB independence march: Top Scottish figures who attended

In the blog for the UKCLA titled Constitutional Pathways To A Second Scottish Independence Referendum, they continued: “Whilst, as a matter of law, the UK Government might continue to withstand the pressure of a renewed pro-independence majority at Holyrood, there have been signs even in unexpected places – notably from within the UK Government itself as well as from within Scottish Labour – that the legitimacy of such a result would be difficult to resist.

“Tactically, the SNP might rely on its Westminster membership to maintain political momentum towards – and to finesse the legal form of – a referendum.

“It could do so with the introduction of a private members’ bill... Such a bill would almost certainly fail to be passed.

The National:

“However, and as advocates for an EU referendum discovered prior to the UK Government’s introduction of the EU Referendum Bill in 2015, these bills can usefully be deployed both to give life to – and to stress test – proposed legislation; to signal action to an impatient audience; as well as to emphasise the sites of political obstruction when the bill falls.”

They dismissed the so-called Plan B alternative to achieve independence through negotiations with the UK Government following an SNP election victory and also pointed to a legal challenge by the Scottish Government to a refusal for a Section 30 order request being unlikely to succeed.

On the former option – which was rejected by the SNP at its October conference last year – they suggested if the PM refused Holyrood a request for independence referendum powers, he was unlikely to take part in negotiations leading to independence.

READ MORE: WATCH: Scottish independence supporters kick off Glasgow march

The academics also say the First Minister’s mandate carries no legal weight. “The Scottish Government’s mandate to hold a referendum – though politically important – seems legally irrelevant,” they wrote. “The doctrine of the mandate plays, at best, a marginal role in UK constitutional law and practice, and in any case what constitutes a mandate is highly ambiguous: how clear does a manifesto promise have to be; is a majority of seats or of votes required (and can these be aggregated from more than one party); and which elections are relevant – to the UK Parliament, which holds the legal competence to dissolve the Union, or the Scottish Parliament, from which the Scottish Government’s authority derives?”

They also said a judicial review challenges against the UK’s refusal – for example on grounds of irrationality or the 2014 precedent – also “seem likely to fail”. McCorkindale is a Strathclyde University senior lecturer and McHarg a professor of law at Durham.