THE SNP’s longest serving MP has issued a fresh warning to his party about the potential consequences on independence by supporting a second EU referendum.

Writing in The National today Pete Wishart, the shadow leader in the House of Commons, said he was fully behind calls for the UK to remain in the EU, but said this ambition should be pursued via stopping the process of EU withdrawal through the revocation of Article 50, rather than through a so-called People’s Vote.

“Revoke is a clear, straight forward route to rescuing the UK’s place in the EU,” he said. “A People’s Vote is a lot more complicated.”

READ MORE: Pete Wishart: People's Vote isn't the answer

He suggested because SNP support was given unconditionally to a People’s Vote – for instance without an agreement all parts of the UK would have to back Leave for the result to be valid – Scotland could end up having to respect a new UK vote to leave even if Scotland voted again to Remain.

“We have not secured any protections for our national interest in a second referendum for our unconditional support. If Scotland therefore votes to remain again (which it will) and the rest of the UK votes to leave (as it very well might) we could be expected to respect the UK wide result in the event of another leave vote,” he said.

He also raised concerns about Kyle/Wilson amendment which calls for MPs to approve the PM’s deal on the condition it is put to a public ballot. He said this could create a precedent for a future Yes vote.

“We would be signing up to the principle of confirmatory referendums when any ‘deal’ is negotiated,” he said. “If this principle was extended to a future successful independence referendum unreconciled unionists would be working ... to undermine that result and the UK would ensure we were given the worst possible ‘deal’ in order to try and reverse the result.”

Wishart’s intervention comes just a day after the First Minister Nicola Sturgeon was one of the key speakers at the “Put it to the People” London rally calling for a second EU vote.