NICOLA Sturgeon has refused to support her party’s Scotland spokesperson over a possible wildcat independence referendum.

The First Minister, who updates MSPs on Wednesday on her next steps on Indyref2, said there was a “need for any process on independence to be legal”.

It followed MP Mhairi Black, the SNP’s shadow Scottish Secretary, saying “there could be mileage” in a consultative referendum that was not approved by the UK Government.

Asked if she agreed with Ms Black, Ms Sturgeon twice declined to say that she did.

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With Boris Johnson refusing to give Holyrood the power for a legally-watertight referendum, former SNP minister Alex Neil has also called for a consultative referendum instead.

However such a vote would almost certainly lead to a legal challenge and a Unionist boycott, and it would deliver little unless the UK Government recognised the result.

Ms Black told the Sunday Times her preference would be to do Indyref2 “by the book” and that a vote backed by law would ensure international recognition.

However she added: “There could be mileage in a consultative referendum because the Scottish question is complicated.

“The current United Kingdom Government position is weak and unsustainable, and if the last five years proves anything, it proves that what happens at Westminster is unpredictable.”

Ms Sturgeon has said she wants Indyref2 this year, but has yet to say how it could happen when the UK Government has rejected a Section 30 order transfer of powers to Holyrood.

After launching proposals for a devolved “Scottish visa” system after Brexit today, the First Minister was asked if she agreed with Ms Black about mileage in a consultative vote.

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She replied: “I will set out my further views on this later in the week.”

Pressed on whether she agreed with her own spokesperson on Scotland, Ms Sturgeon again refused to support Ms Black.

She said: “I will set out my views on this. I’ve been very clear about the need for any process on independence to be legal and that is my position.

“I think it’s also Mhairi Black’s position as well. I will set out my further views on this later on this week.”