A CENTRAL pillar of the relationship between the UK Government and devolved nations is in a “precarious position” after Holyrood voted to reject the controversial power grab bill, an expert has warned.

Last week MSPs voted by 90 to 20 against consent for the Internal Market Bill, as it “constrains the competence of the Scottish Parliament and breached international law”.

The Scottish Government has now called on the UK Government to withdraw the legislation, arguing consent is required under the Sewel Convention.

Under this agreement, the UK Government “will not normally” legislate in devolved matters without the consent of the devolved nations.

Before Brexit, the only time Holyrood voted to deny consent was on aspects of the Welfare Reform Bill in 2011, which led to amendments. But the latest rejection means the Internal Market Bill is expected to become the third piece of Brexit legislation forced through without consent from all devolved nations.

Following the Holyrood vote, Cabinet Office minister Michael Gove indicated the UK Government will press ahead with the bill.

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Akash Paun, senior fellow at the Institute for Government think tank, said the withholding of consent by MSPs was a significant moment, as disputes over the Sewel Convention have been “very rare”.

“It has been used for over 200 Acts of Parliament and the Scottish Parliament has only voted against giving consent on now four occasions,” he said.

“So it doesn’t happen very often and it is certainly a significant moment. From my perspective it has been a really fundamental pillar of the devolution settlement as it is that convention operating that has given each of the devolved nations the sphere of political autonomy within devolved areas.

"But in the end, the legal position has remained unchanged – [UK] Parliament can legislate in devolved areas if it chooses to do so.”

A commitment was made to put Sewel on a “statutory footing” following the 2014 independence referendum and it was subsequently written into in the Scotland Act of 2016.

But in 2017, when the UK Government was challenged over the triggering of Article 50 without parliamentary consent, the Supreme Court ruled it was not legally enforceable.

Paun said the Sewel Convention was in a now “precarious position”, although he pointed out consent has continued to be given by the Scottish Parliament for various other Acts of Parliament at Westminster.

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“In various areas it has continued to operate, but it has broken down clearly with the UK Internal Market Bill,” he said.

“The bill wasn’t developed at all in partnership with the devolved administrations, it wasn’t shared in advance.

"If the UK Government then decides to press ahead with the legislation, you can see why people at the devolved level will then start asking what is the point of the consent process in the first place.”

The bill has been passed by the Commons and is due to have its second reading in the House of Lords on October 19.

Constitution Secretary Michael Russell said: “This bill represents an assault on devolution, the likes of which has not been experienced since the current Scottish Parliament was established.

"It also breaches international law. As the Scottish Parliament backed the Scottish Government’s motion to refuse legislative consent for it, we now urge the UK Government to withdraw it.”

He added: “However if the UK Government does not drop this unnecessary and damaging bill, we hope that the House of Lords will throw it out as they have been threatening to do.

“But if they fail too then, as we have said, we will consider further options up to and including legal action.”