JOANNA Cherry sent Whatsapp messages to SNP MPs telling them they would be in breach of party rules if they publicly backed a candidate in the Edinburgh Central selection contest after her rival Angus Robertson had lobbied MPs to endorse him, The National has been told.

A supporter of Cherry’s bid to win the SNP’s nomination for the key target seat at next year’s Holyrood election said her intervention followed Robertson’s trying to get the public backing of his former Westminster colleagues.

“Angus was going around trying to get endorsements from MPs. Various MPs came to Joanna and told her ‘this is what he is doing and you should do something’. They said it was a breach of the latest selection rules. They were saying ‘Are you going to announce our support before he gets our support?’”, the insider said.

“Joanna told them ‘this is a selection process. It’s for the members [of Edinburgh Central] and not for elected members to be commenting on it one way or the other. Keep out of it, it’s not going to be who is in who’s camp.’ So she circulated the information to the rest of the group.”

As the row intensified Robertson yesterday posted a photograph on Twitter taken outside the House of Commons, showing Cherry alongside fellow SNP MPs holding up a sign ‘I’m nominating Angus Robertson MP. #Vote Angus” during the SNP’s depute leadership contest in 2016.

The contest was won by Robertson ­­– who secured more backing from MPs and MSPs than his rivals Tommy Sheppard, Alyn Smith and Chris McEleny.

Defending the right of MPs to show preferences in internal contests, Robertson wrote: “Endorsements are a key part of candidate selection process across the democratic world from the US Democrats to @theSNP. Here are some of the parliamentarians who nominated and endorsed me for the SNP depute leadership. #democracy.” But the Cherry camp responded saying the deputy leadership contest and the selection process for candidates are not comparable as in the former MPs, MSPs and all members can vote, while in the latter only branch members can do so.

Cherry and Robertson are both vying to be selected as the SNP’s candidate to fight the seat of Edinburgh Central at next year’s Holyrood election. Some 1200 members of the SNP branch will vote on who they want when the ballot opens in June.

The National yesterday revealed a dispute between Cherry and fellow MP Alison Thewliss over whether MPs could publicly support candidates.

Cherry told MPs in a Whatsapp exchange last week they would be in breach of party rules to do so. Alison Thewliss, the MP for Glasgow Central, disagreed. The Edinburgh MP also argued endorsements may not be in the interest of longer term party unity.

Guy Ingerson, the Greens’ candidate for North East Scotland at next year’s election, posted a tweet of Cherry endorsing Doug Thomson when he was standing to win the SNP’s nomination for Edinburgh South in 2017.

He wrote: “Hasn’t Cherry endorsed candidates herself in the past? This battle between the populist nationalist & liberal centrist factions is certainly interesting if nothing else...”

Meanwhile, Alyn Smith, the SNP MP for Stirling, said the party should ban all endorsements. He said: “I’ve been kicking around long enough to remember when endorsements weren’t the done thing, and personally I’d ban them altogether as we’re all team SNP. I’m conscious with that that we can’t take the politics out of politics but we all need to remember our opponents watch our Twitter too and there’s a number of bad actors online trying to just sow discord. I’ll back any duly selected candidate and trust the members to make a choice, often a tough choice between strong candidates. I have in a few cases given endorsements myself, but I’ve never seen them make any difference.

"Any candidates seeking a selection should worry less about people bumping their gums on Twitter and get out leading campaigning activity and speaking to members that way.” Edinburgh Central is a target seat for the SNP, held by former Scottish Tory leader Ruth Davidson who is standing down before the election.