NICOLA Sturgeon has given a withering response to Alister Jack's suggestion that the UK Government could agree to a second independence referendum if polling consistently shows 60% of Scots support having one.

In an interview published today the Scottish Secretary said backing for a new vote  – rather than independence itself – would have to be at 60% for a “reasonably long period” before ministers in London would agree to a new vote.

It is the first time in the last few years that a UK Government minister has offered to define specific conditions for backing another vote on Scottish independence.

The First Minister dismissed his intervention when she was asked about it today at her coronavirus briefing.

"I am not going to get diverted in a Covid briefing into responding to Secretary of State, I think it was the Secretary of State, making up constitutional rules as he goes along.

"We have constitutional rules that are pretty well established in a democracy. If a party wins an election on a particular proposition they should get to implement that proposition," she said.

Jack's comments come after Cabinet Office minister Michael Gove said the UK Government would not stand in the way of a second referendum if it was the “settled will” of the Scottish people.

READ MORE: Alister Jack says indyref2 could take place if support for Yes is above 60 per cent

Asked what would constitute the “settled will”, Jack said: “If you consistently saw 60% of the population wanting a referendum – not wanting independence but wanting a referendum – and that was sustained over a reasonably long period, then I would acknowledge that there was a desire for a referendum. Anyone can see that.

“But that’s not where we are and it’s not how I perceive things to be. I think I’m broadly where the public are, which is that now is not the time to be having a referendum.

“We’ve had one, we’ve made our decision, let’s get on and rebuild the economy and rebuild people’s lives.”

The SNP won the Holyrood election in May and went into government in Edinburgh for a record fourth term. The party won 64 seats, one short of a majority, but along with the seven Scottish Greens MSPs there is an independence majority in the Scottish Parliament.

READ MORE: Greens' chiefs Patrick Harvie and Lorna Slater urge members to back pact

Both parties made manifesto commitments to hold an independence referendum in the current parliamentary term so long as the coronavirus pandemic has passed.

In interviews before the election and afterwards the First Minister has said she wants a vote to take place by the end of 2023 on the condition the Covid-19 crisis is over.

Speaking to The National yesterday, the SNP's Westminster leader Ian Blackford said his party had a 'responsibility' to deliver indyref2 following the election result in May.

"We had an election in May. There is a clear majority for an independence referendum in the Scottish Parliament and it is about recognising we have that mandate, we have the backing of the people who went to the polls in May of this year and a responsibility we have to execute that mandate,” he said.

The most recent published opinion poll on whether there should be a referendum was conducted by Redfield & Wilton Strategies on August 4 and 5.

It found 42% support holding a referendum more than a year away but within five years, while 40% said they oppose having one in this timescale. Voting intention gave the No side a lead of 3%.

READ MORE: Ian Blackford: SNP handed ‘responsibility’ to deliver independence vote

Jack's comments come after the First Minister and Scottish Green leaders Patrick Harvie and Lorna Slater entered into a co-operation agreement, with part of the their pledge being to hold another independence referendum.

Last week, announcing the deal with the Greens, the First Minister said the new arrangement between the two pro independence parties would make it 'impossible' for Prime Minister Boris Johnson to reject a new vote.