NICOLA Sturgeon has denied “weaponising” children’s rights in order to pick an election fight with Westminster after criticism from Scotland’s top lawyer.

The First Minister was put on the defensive after she and her ministers repeatedly accused the UK Government of trying to undermine children’s rights.

The UK Government’s law officers last week raised a legal challenge against a recent Holyrood Bill intended to incorporate the UN Convention on the Rights of the Child (UNCRC) into Scots law on the grounds it encroached on Westminster’s powers.

The UK Government warned Edinburgh last month about specific legal issues with four sections of the Bill and asked for changes, but deputy First Minister John Swinney refused, calling it a “menacing” letter.

READ MORE: UK Government refers two Holyrood Bills to Supreme Court

After the Bill was passed unanimously by MSPs, the UK law officers, in a wholly foreseeable move, then referred the disputed sections of the Bill to the UK Supreme Court for a definitive ruling on their competence.

It means the Bill is now on hold and will not receive royal assent and become law. The Court can either uphold it or send it back to Holyrood for changes.

The referral has since been cited by Ms Sturgeon and her ministers as an example of Westminster trying to undermine devolution and dilute children’s rights.

Ms Sturgeon cited it in Tuesday's STV leaders debate.

The next day at PMQs, SNP Westminster leader Ian Blackford said the UK Government was “shamefully” taking the Scottish Parliament to court, and asked Boris Johnson to explain “how protecting children’s rights in Scotland threatens the Tory Government in London?”

Mr Johnson called the attack “complete nonsense” and accused the SNP of trying to “stir up constitutional chaos and create another fictitious bone of contention”.

The exchange prompted Roddy Dunlop QC, the Dean of the Faculty of Advocates, to take issue with Mr Blackford’s comments via social media.

He wrote on Twitter: “I do not wish to wade into a political quagmire. But with respect it is not “shameful” for this challenge to be brought. No one queries the rights of children. 

“The question is the competence of Scottish Parliament. 

“It’s a constitutional question, not a political one.”

Mr Dunlop went on: “It [the UNCRC Bill] is either incompetent - in which case it cannot legally be done - or it’s not. That’s a question of constitutional law, regardless of political support. 

“And as for timing, there is a 4 week time bar for references like this, so that is also not a political question.

Whether a bill should be voted for is a political matter. Whether a bill is outwith legislative competence is purely a question of constitutional law, and has nothing to do with politics.”

Launching the SNP manifesto today, Ms Sturgeon said the Tories would “seize any chance they can get to overturn any decisions of the Scottish Parliament that get in their way.

“They are even going to court to challenge a law passed unanimously in the Scottish Parliament to protect children’s rights. Who knows what’s next?”

In a Q&A with the media afterwards, Ms Sturgeon was asked about hers, Mr Blackford’s and Mr Dunlop’s comments on the issue, and if she was “weaponising the issue of children’s rights simply to start a fight with the UK Government to whip up independence support”.

She suggested Mr Dunlop's opinion was little different from anyone else's.

She said: “The Dean of the Faculty of Advocates is entitled to his opinion. Everybody’s entitled to his opinion. It doesn’t necessarily mean that is right and that my opinion on this, or the SNP’s opinion on this, is wrong. 

“This is a devolved Bill that makes specific reference about only applying to the things that are within developed competence under the Scotland Act.

"So by its nature it’s devolved.

“These issues about competence were raised in  the passage of the Bill.

“The Tories put down probing amendments. They didn’t push those amendments. 

“So clearly they were satisfied with the answers and the Bill was pushed unanimously.

“So it’s a Bill within devolved competence. The Presiding Officer of the Parliament, not a known Nationalist, certified it as being within devolved competence, and we now have a UK Government that wants to challenge it.

“The leader of the Scottish Tories says this is just small technical reasons they want to challenge on. One of the sections of the Bill they’re challenging is Section 6, which says it’s unlawful for any public authority to do anything that is not compatible with the requirements of the UN Convention on the Rights of the Child.

"That’s the fundamental part of the Bill.

“Effectively, the UK Government just doesn’t want to be bound by that in terms of what they’rte able to do in Scotland. That’s not technical, that strikes at the heart.

“Secondly, if the UK Government thinks there’s technical issues about competence here, wouldn’t it be better just to take away those issues by the UK Government saying they’ll comply with the UN Convention on the Rights of the Child as well?

“What is it the UK Government is planning to do in Scotland they worry is going to breach the UN Convention on the Rights of the Child?

“Maybe they should tell us that before we go much further.”

A UK Government source said: "This delay could to the legislation easily have been avoided.

"Sadly, it appears the Scottish Government are more interested in stirring a constitutional row than getting the UNCRC Bill into law at the first opportunity".