HUMZA Yousaf has accused Unionists of trying to “shut down” debate on independence in the growing row over the funding of the Scottish Government’s work on the subject.

The First Minister said it was a sign of his opponents’ weakness that they were trying to limit discussion rather than putting forward a positive case for the status quo.

He said: “I believe we can win any referendum on independence whenever that is and I would say, Bring it on.”

He refused to say if Scottish Government officials would follow forthcoming Cabinet Office guidance on the line between working on devolved and reserved matters.

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The FM was speaking on the eve of launching the fifth paper in the Building a New Scotland series which began under his predecessor Nicola Sturgeon.

Thursday’s publication will cover citizenship, migrant rights, passports and diplomats. 

The papers have infuriated some Unionist MPs and peers, who object to taxpayer-funded neutral civil servants working on a project seen by its critics as overtly party political.

Labour’s Lord George Foulkes this week called for “sanctions” to be imposed on Scottish ministers who spend public money on work outside the bounds of devolution.

Calling the latest paper “deliberately provocative", he suggested ministers could be fined personally if they order officials to work on reserved matters such as independence.

The head of the UK civil service, the cabinet secretary Simon Case, last week told peers it would be “unusual and worrying” for officials to work on breaking up the UK.

He said new guidance on the issue would be issued to civil servants “within weeks”.

All civil servants are part of the UK service; in Scotland their job is to serve Scottish ministers, but they must also observe the UK civil service code.

Mr Yousaf discounted the idea of creating a stand-alone Scottish civil service.

He said: “I'm quite happy with the excellent support that we get from the civil service.

“I know - from my regular conversations with the Permanent Secretary and others - there's a really good working relationships in our Civil Service here in Scotland and their UK counterparts.

'What we won’t countenance and stand for is any of the Westminster establishment, be it the UK Government or indeed those in the House of Lords, trying to curb the work that we are democratically elected to do.

“We have a mandate in relation to independence and there’s a pro-independence majority in the Parliament and we'll continue to make the case for why we think the best future for Scotland is one as an independent nation.”

Asked what he would do if civil servants were told they couldn’t work in reserved areas such as independence, he said: “Well, first and foremost, that's not what's being said. 

“We have very clear parameters where we can work, and the work that we're doing in relation to the Building a New Scotland series of papers… are well within the scope of work that we are able to do.

“What I would say to those UK parties, be it Scottish Labour, be it the Conservatives, is that what have they got to fear from us making the positive case?

“This to me is a demonstration of just how weak their case is, if they're trying to shut down what we have been democratically elected to do.”

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Asked if he expected civil servants working in Scotland to follow the new guidance, the First Minister did not commit to them doing so.

He said: “We'll wait to see what that guidance has to say, but I'm very, very clear we have - as  you'd imagine, after the Supreme Court judgement in particular - advice on what our civil servants can and can't do.

“The work to advance the case of independence, which we were democratically elected to do, and to make that case, that is perfectly within our jurisdiction.”

Asked what merit there was in the “dead work” of the Building a New Scotland papers given there was no prospect of Indyref2 in coming years, Mr Yousaf refused to accept the premise.

He said: 'I believe that we've got to increase the political support in order to get a referendum and the way you increase that political support is making the argument for independence.

“That's why this series of papers has been launched, because we're very confident in our argument and we think we have the winning argument.

“Now there's plenty of other people on the other side of that debate, who believe we don't have the winning argument. 

“What I would say to them [is] instead of trying to shut us down, instead of trying to stop us from doing the work we're wanting to do, bring your arguments forward, let's have that discussion and that debate around the merits of independence.

“Instead of trying to shut us down, let's have a free, frank and open discussion.”

Asked if his opponents were trying to shut him down because they saw the SNP and Yes movement as weak, the First Minister said he couldn’t disagree more.

He said: “They’re doing that because they are weak. 

“If they were strong in their arguments, they would take us on. They would say right, okay, let's have that referendum. Let's have that debate. We will win it. 

“And that's the position that I'm in. I believe our arguments are strong. I believe we can win any referendum on independence whenever that is and I would say, Bring it on.

“Instead of trying to shut us down, instead of trying to shut down the debate and the argument, get on with it, make your case.

“If there’s a positive case there to be made, let's hear it. And let's have that discussion and that debate and ultimately put it to the Scottish people.”