Airdrie & Shotts’ retiring MSP says the SNP should “work in partnership” with the new Alba party formed by Alex Salmond to achieve a pro-independence supermajority in the new Scottish Parliament.

Former cabinet minister Alex Neil issued a statement encouraging tactical voting in the regional list ballot and said: “We must act as a united front to maximise the independence vote [and] we must all put our country first.”

Mr Neil, who is standing down after 22 years at Holyrood, issued a statement saying that a pro-independence supermajority is required to facilitate a second independence referendum, as the combined SNP and Green majority of nine in the previous parliament had resulted in “zero progress”.

He said: “We cannot allow that situation to continue – the experience of the past five years teaches us that a supermajority of pro-independence MSPs will be needed to force Boris Johnson’s hand on the constitutional question.

“The self-interests of individual parties and personalities are secondary to the needs of the Scottish people – the SNP is the leading driver for constitutional change, but to achieve our primary objective we must be big enough to work with others who are on our side.

“In nearly every region the SNP’s huge sway over such a large number of constituencies means it’s impossible for it to win many list seats; in such circumstances it makes sense to have an agreement between the pro-independence parties to vote tactically.

“Electing a supermajority of pro-independence MSPs must surely be preferable to allowing anti-independence MSPs to get in by default because the pro-independence parties haven’t supported each other.”