Devolution is becoming “unworkable” as a result of Scottish laws being overturned by the UK Government, says First Minister Humza Yousaf.

In a ramping up of tensions between the two parliaments, Mr Yousaf says that the blocking of legislation passed by Holyrood means that devolution can no longer guarantee even a limited measure of self-government.

He has appealed to the Labour leader Sir Keir Starmer to stand up for the powers of the Edinburgh-based parliament after the Tory Government overturned Scottish law using the Internal Market Act.

It was introduced to create a level playing field for trade across the four nations after Brexit, but the SNP says it enables Westminster to sabotage Scottish legislation..

The SNP leader believes it is being applied in areas which are specifically devolved or are in breach of the Sewel Convention which states that the UK Parliament will not normally legislate with regard to devolved matters without the consent of the Scottish Parliament.

His exasperation boiled over after the UK Government applied conditions to Scotland’s Deposit Return Scheme which led to it being delayed from next March until October 2025.

Mr Yousaf said: “The last few weeks have brought into sharp focus the grim reality that under Westminster control, even the limited measure of self-government that devolution provides is no longer guaranteed.

“It is the case that this Tory Government has ensured that devolution in Scotland is becoming unworkable.”

He added: “We are facing a steady erosion of the powers of our Parliament, the routine undermining of the Sewel Convention, UK Government Ministers blocking laws passed by a majority of MSPs in explicitly devolved areas, and senior Tories interfering in the Scottish Government’s vital work abroad.

“All of this amounts to a pattern of unprecedented assaults on the Scottish Parliament – putting the entire devolution settlement at risk. Addressing this effectively requires urgent and meaningful action from all political parties which supported the establishment of Holyrood almost 25 years ago.

“Yet, when it comes to standing up for our Parliament, Keir Starmer has been posted missing. Labour in London or Scotland have done absolutely nothing to protect people here from the Tories and their attempts to stop the Scottish Government from legislating in entirely devolved areas.

“There is now a real opportunity for Keir Starmer to show that he supports the basic principles of democracy, and devolution. He must recognise that urgently, or his party risks ending up on the wrong side of history.

“Scotland’s interests cannot be properly served by this Westminster system, and our best hope for the future lies in becoming an independent country – in a partnership of equals with our friends across the UK. That will allow us to make a real different for our people, our planet, and our future prosperity.”

UK Government supporters will argue that intervention has been necessary to check unfettered spending and reckless policies that add to the deficit and leave taxpayers picking up the tab.