Humza Yousaf has been chided by the SNP’s longest serving MP after repeatedly snubbing a request to appear before the Commons Scottish Affairs Committee.

Committee chair Pete Wishart said it was “disappointing” Mr Yousaf was the only living first minister to have declined to give evidence on relations with the UK Government.

This was despite Mr Yousaf being urged to “reconsider” a previous refusal and being offered any date “which might be convenient” for him.

It emerged earlier this week that Alex Salmond will discuss the subject on February 19, with MPs hearing from Nicola Sturgeon, Lord Jack McConnell and Henry McLeish later this year.

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The six former prime ministers since the start of devolution 25 years ago have also been invited to appear, with Lord Cameron and Sir Tony Blair already giving written evidence.

The cross-party committee, which includes Scottish Tory leader Douglas Ross, launched its inquiry into intergovernmental relations last July.

In a letter to Mr Yousaf on December 18, Mr Wishart said that further to a letter sent on July 3, the committee wanted to “reiterate its open invitation to you to give evidence to the Committee at a date which might be convenient to you”.

He went on: “This would be an opportunity to discuss policy areas related to recent inquiries and your priorities as First Minister. 

“It would also be a chance for you to comment on current intergovernmental relations between the UK and Scottish governments, which is the focus of the Committee’s current inquiry on Intergovernmental relations: 25 years since the Scotland Act 1998. 

“We hope you will re-consider our invitation, and we look forward to hearing from you.” 

But on January 4, Mr Yousaf again refused to appear, citing a full diary

The first minister, who launches the SNP’s general election campaign tomorrow despite no election date being set, said Constitution Secretary Angus Robertson would go instead. 

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Mr Yousaf wrote: “Unfortunately, due to my extensive commitments as First Minister, I am unable to accept the invitation to appear before the Committee.  

“As the Committee is aware, I am accountable to the Scottish Parliament for the decisions and actions of the Scottish Government. 

“Sessions such as weekly First Minister’s Questions and my evidence sessions with the Scottish Parliament Conveners Group are an important feature of my commitment to ensuring that the Parliament can fully discharge its essential scrutiny function.

“I understand that the Cabinet Secretary for Constitution, External Affairs and Culture, Angus Robertson, has accepted an invitation to discuss the Scottish Government’s written evidence to your inquiry… in early March. 

“I am sure the Committee will welcome the opportunity to discuss these important matters with Angus.” 

Mr Wishart said: “It’s disappointing that the First Minister isn’t able to give evidence to the Committee, citing a similar outlook to previous serving First Ministers - that his primary responsibility, while in office, is to the Scottish Parliament. 

 “The invitation remains open if Mr Yousaf’s availability changes.”