THE SNP’s longest-serving MP has hit back at Alex Salmond’s call for Yes candidates at the next General Election as “ridiculous”.

Earlier, The National told how the Alba party leader had written to the SNP’s MPs at Westminster urging them to back Alba’s bid for a ‘Scotland United for Independence’ approach where pro-independence parties would only put forward one candidate.

In a letter to SNP MPs, Salmond claimed the proposal and the reasons for it are “imperfectly understood” and he was therefore writing to MPs in the House of Commons to gather support for the plan.

READ MORE: Westminster blocks key part of Scottish deposit return scheme

The former first minister said that as the SNP have decided to engage in an “internal discussion”, through the upcoming independence convention at the end of June, there is “no opportunity” for Alba to present the plan at a wider Yes summit.

Salmond had previously written to First Minister Humza Yousaf regarding the electoral plan, but has not yet had a reply.

However, Pete Wishart, the SNP’s longest-serving MP, branded the plan “ridiculous” on Twitter and hit out at the Alba party as “toxic”.

“It's a ridiculous proposal designed to get an unelected party MPs on the back of SNP votes,” he wrote.

“We'd be severely punished by the Scottish electorate if we partnered a toxic party on 2% of the vote that has never won an elected representative in any election.”

"All for working together if we can get a code of conduct to underpin it," Wishart added, in response to calls for a wider discussion in the Yes movement.

"But this proposal would kill any chance of independence. Alba in their current state are totally toxic and would put people off if they were in any way associated with the mainstream movement."

Of the 45 SNP MPs currently in the House of Commons, only Wishart engaged with Salmond’s proposal on social media.

READ MORE: Humza Yousaf urged to 'hold nerve' on deposit return scheme

Salmond’s electoral plan would see “existing seats” held by pro-independence MPs fought by that candidate, or one chosen by the party which holds it, hinting that this would allow Alba MPs Kenny MacAskill to stand in East Lothian, and Neale Hanvey in Kirkcaldy and Cowdenbeath.

This would be in place for the 47 seats currently held by the SNP and Alba, with the remaining ten seats up for grabs “distributed among the participating parties with the SNP again receiving the lion’s share”.

“Each party would agree to have as the first paragraph in their manifesto, that they are standing seeking a popular mandate to negotiate independence from Westminster and under the respective candidate descriptions ‘SNP, Scotland United for Independence’, ‘Green Party, Scotland United for Independence’, ‘ALBA Party, Scotland United for Independence’, etc,” Salmond wrote in his letter to MPs.

“It might also be beneficial to contest a couple of seats with representatives of the non parliamentary independence parties or non political party affiliated prominent independence supporters, but I accept that is a matter for more detailed discussion.”