Nicola Sturgeon's new plans for a second referendum on independence could be derailed by a legal challenge, constitutional law experts have told BuzzFeed News.
The first minister laid out her government's plans for the new Scottish parliament term on Tuesday afternoon, including a push on draft legislation to allow another vote on independence.
But lawyers warned that unless the UK government gives the Scottish government the power to hold the vote, as happened with the 2014 referendum, the legislation would almost certainly be challenged in court as being outwith the powers of Holyrood.
Sturgeon has repeatedly said she is "highly likely" to hold a second referendum on independence if the UK government settles for a so-called hard Brexit, which would see the country taken out of both the EU and the single market.
Tuesday's programme for government document states: "We will publish for consultation a draft referendum bill, in order that it is ready for introduction should the Scottish government conclude ... that independence is the best or only way to protect Scotland’s interests in the wake of the EU referendum."
However, the Scottish parliament's presiding officer – the equivalent of the Westminster parliament's speaker – will be able to challenge the bill's legality once it's presented to parliament if he deems it to be outside the powers currently devolved to Holyrood on the basis of independent legal advice.
The referendum in 2014 was only able to take place legally after the UK government temporarily transferred the power to hold one to the Scottish government in 2012's Edinburgh Agreement, but there is no guarantee such a move would be repeated.
Dr Andrew Tickell, a law lecturer at Glasgow Caledonian University who wrote about the row when it erupted during Alex Salmond's tenure as first minister in 2010, said it was a "tricky" legal issue but any referendum bill presented to the Scottish parliament without the prior agreement of the Westminster parliament would be challenged.
"There are legal arguments to be made that Holyrood does have legal competence to hold such a referendum, but the peg is pretty shoogly [shaky]," Tickell told BuzzFeed News. "Without Westminster's cooperation, even if it got through Holyrood, the issue is bound to be litigated."
He added: "There's [the presiding officer's] certificate on one hand, and on the other, a whole bunch of folks who might sue (including ordinary punters with money to burn in court costs)."
Professor Aileen McHarg, who specialises in Scottish constitutional law at Strathclyde University, told BuzzFeed News that a referendum bill introduced by Sturgeon without the support of the presiding officer could still technically pass through Holyrood, but then it would face legal challenges from elsewhere.
"Irrespective of what the [presiding officer] says about competence, the legality of such a bill is certain to be challenged," said McHarg.
"That could happen either at the end of stage three [of voting in Holyrood] – the UK government's law officers, or the Lord Advocate could make a reference to the supreme court. Or, if that doesn't happen and the bill is enacted, anyone with an interest could seek judicial review."
The legal battle could be avoided should Theresa May decide to transfer the power to hold a referendum to Holyrood once more, but the new prime minister has been cold on the idea of a second IndyRef since she took over from David Cameron in the wake of the Brexit vote.
Speaking on The Andrew Marr Show on Sunday, May said: “I don’t think it’s a question of whether there could be a second referendum, it’s whether there should be a second referendum.”
She added: “I think if you look at some of the results that are now coming out of polling in Scotland, they suggest that the Scottish people don’t want there to be a second referendum.”
A spokesperson for the Scottish parliament said that as Sturgeon's referendum bill is just entering a consulting stage, the presiding officer currently has no role in deciding whether or not it's within the powers currently devolved to Holyrood.
The spokesperson added: "Until the presiding officer has seen the actual bill that is to be introduced he cannot (and would not) give an opinion on whether the bill is legislatively competent."
However, a Scottish government source said the vote in 2014 would act as a "clear precedent for a legally watertight referendum".
Jamie Ross is a Scotland reporter for BuzzFeed News and is based in Edinburgh.
Contact Jamie Ross at firstname.lastname@example.org.
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