THE SNP's most senior MP, Pete Wishart, has resigned from the party's frontbench at Westminster following Stephen Flynn taking over as group leader.

Wishart said in his resignation letter that he was “bemused” why Flynn had sought a change from Ian Blackford's leadership.

The Perth and North Perthshire MP announced he would be stepping down as the group’s Department for Environment, Food and Rural Affairs (Defra) spokesperson.

In his letter to Flynn, he said: "It is with regret that I write to inform you of my decision to resign as the Westminster Group's Defra spokesperson. 

READ MORE: Scottish independence poll raised by Stephen Flynn at first PMQs

“I have only been in this role for a few short weeks, but I have immensely enjoyed building positive relationships with Scotland's farmers, fishers and the wonderful people who work in the NGO community for animal welfare and environmental charities. 

“In my 21 years in parliament, I have served as spokesperson in a variety of front bench roles including as our shadow leader of the house and chief whip. I have never had the opportunity to experience the delights of the backbench and I look forward to serving your leadership from there."

Wishart backed Alison Thewliss for the Westminster leader role after Blackford stepped down. Party insiders told The National that Blackford “jumped before he was pushed”. 

Wishart's letter continued: "I note that you hope to bring positive change to the way the group is run and that you wish to reset the relationship with colleagues in Government and in the Scottish Parliament.

"The latter, as I'm sure you are aware, is extremely important for the general culture within the party and I wish you well in these endeavours. The Westminster group is unique in the respect that we are a party of power in a parliament, in which that power can never be exercised.

"Many of us carry the scars following the many attempts to manage that unfortunate tension over the course of the years. I remain bemused as to the reasons why you felt it was necessary to seek a change in our leadership, particularly when we see yesterday's opinion poll, which shows support for independence at a near all-time high and support for the SNP at Westminster at an unprecedented 51%."

"Usually change of this significance accompanies failure, whereas we are looking only at sustained and growing success as a movement and party.

"I am sure that this is something that will become apparent to me during the course of your leadership. I also look forward to learning at first-hand what you hope to do differently in the day-to-day management of the group.

"Lastly, I wish to assure you that you have my full support and I remain at your service if you do wish to make use of my experience in the Westminster group. We are always better when we work together, fully support our Government and stand side by side with all colleagues regardless in which Parliament they serve."

On Wednesday, when pressed on the idea of a split between "Sturgeon loyalists and Sturgeon sceptics", SNP MP Stewart Hosie said this was a "complete fiction"

Flynn replied to Wishart and thanked him for his time on the party’s front bench.

He said: “Pete, thank you for your exemplary service for the SNP on the front bench in Westminster over so many years. 

“As ever, my door remains open and I look forward to working with you as we support colleagues in Holyrood, hold the Tories to account, and work to deliver Independence."