Senior SNP MP criticises new Westminster leader
SNP's longest-serving MP has quit the party's frontbench team in the Commons after criticising its new Westminster leader.
Pete Wishart said he was "bemused" as to why Stephen Flynn had sought to replace Ian Blackford in the role.
And he claimed there had been no opportunity to discuss Mr Flynn's plans for the group ahead of Tuesday's vote. 
Another prominent SNP MP, Stewart McDonald, has also said he will be stepping down as defence spokesman.
In his resignation letter, he said the SNP was at its best "when we collaborate as a united party" and urged the new leadership to "keep this at the forefront of their mind and work in that spirit across the party".
Mr Flynn defeated Alison Thewliss - who is seen as being closer to Nicola Sturgeon - in the ballot of SNP MPs.
re had been rumours for some time that he was "on manoeuvres" to replace Mr Blackford, who had served as group leader for five years and was also a close ally of Ms Sturgeon.
Mr Blackford announced last week that he was standing down from the role, with the vote to replace him being held just days later.  
Mr Flynn has already replaced Owen Thompson as chief whip with Martin Docherty-Hughes being appointed to the role, and there are more changes expected to be announced in the coming days. 
Allies of the new leader have suggested he wants to have a smaller front-bench team, allowing other MPs to focus on constituency work and campaigning for independence.
re have also been reports that Mr Flynn intends to take a more robust approach to the group's relationship with Ms Sturgeon and the SNP government at Holyrood. 
Mr Wishart, who has been an MP since 2001, had been the party's agriculture spokesman in the Commons. 
In his resignation letter to the new leader, he wrote: "I remain bemused as to the reasons why you felt it was necessary to seek a change in our leadership".
Highlighting an opinion poll published on Wednesday that suggested support for independence was at 56% and the SNP at 51% for a general election - higher than other recent polls - he added: "Usually change of this significance accompanies failure.
"We are looking only at sustained and growing success as a party and a movement and party.
"I am sure that this will become apparent to me during the course of your leadership. I also look forward to seeing first-hand what you hope to do differently in the day-to-day management of the group."
He also appeared to take aim at a perceived lack of communication from Mr Flynn - who was little known outside political circles before winning the leadership vote - about what he planned to do now he had taken over from Mr Blackford.
Mr Wishart said: "We never had an opportunity to discuss your plans for the group, neither when you were canvassing opinion for a leadership challenge nor at any point during the very short campaign for the leadership itself."
He said he noted that Mr Flynn wished to "reset" the relationship between the Westminster group and its colleagues in the Scottish government and Scottish Parliament. 
Mr Wishart added: "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."
Despite the criticisms, Mr Wishart said Mr Flynn would have his full support, adding: "We are always better when we work together, fully support our government and stand side by side with all colleagues regardless of which parliament they serve."
Mr Flynn thanked Mr Wishart for his "exemplary service" to the SNP over many years, adding: "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.''
Scottish Conservative chairman Craig Hoy said the SNP were "fighting like ferrets in a sack" and described Mr Wishart's letter as "the latest evidence of the deep splits running through the SNP".
He added: "Policy and personal disagreements are emerging all the time as the party's reputation for iron discipline under Nicola Sturgeon disintegrates".
It comes the day after another senior SNP MP - Stewart Hosie - told BBC Scotland that reports of division within the party's Westminster group were "complete fiction".
Mr Hosie, who backed Mr Flynn for the leadership, added that "not one word of that is true" and he had "no idea where these stories have come from".
re had been reports for several months that many SNP MPs were increasingly unhappy with Mr Blackford's leadership, particularly after he urged them to give their full support to former chief whip Patrick Grady.
Mr Grady was suspended from the party and the Commons earlier this year for sexual misconduct.
Mr Flynn denied just two weeks ago that he was plotting to oust Mr Blackford alongside colleagues from the so-called Tuesday Club - a group of male SNP MPs who are said to hold regular five-a-side football, beer and curry nights. 
Pete Wishart's letter has rather let the air out of the SNP's "nothing to see here" position on its Westminster leadership change.
first minister had insisted the move to replace Ian Blackford was not a coup. MP Stewart Hosie said talk of splits was "complete fiction".
But Mr Wishart has now confirmed that Mr Flynn had been canvassing colleagues for some time, while directly accusing him of "seeking a change in our leadership". 
f those wonderful political things where a party sticks doggedly to a position despite the fact nobody actually believes it.
It is an understandable tactic in a way, and one employed by every party at one time or another. It's obviously in the SNP's interests to close ranks and insist everything is fine, as doing anything else would only provide ammunition for their opponents.
Mr Wishart has been at Westminster longer than any of his colleagues - he knows exactly what his intervention means, as a jarring outbreak of reality amid the spin.