A former SNP leadership candidate has said he quit the party after becoming disillusioned with Nicola Sturgeon’s “neo liberal” economic policies.

Bill Wilson, who was an MSP for four years, told this newspaper he joined the Scottish Greens after nearly three decades in the Nationalists.

Wilson shot to prominence in 2003 when, as an ordinary party member, he mounted a leadership challenge to John Swinney, who at that point was at the helm of the party.

Although Swinney won comfortably, Wilson’s leadership bid is believed to have wounded the SNP heavyweight, and he resigned within twelve months.

Wilson was elected as an MSP for the West of Scotland in 2007 and served for a single term before losing his place in the Parliament.

READ MORE: French-born SNP candidate urges EU nationals to ‘send message’ to PM on May 23

However, a picture was posted on social media yesterday which showed Wilson campaigning for the Scottish Greens in Edinburgh.

Speaking to this newspaper, he confirmed that he left the SNP after the last Holyrood election:

“During the Scottish parliamentary elections, Nicola Sturgeon was arguing that taxation is about raising income, whereas [Scottish Green MSP] Patrick Harvie was arguing it is also about creating a more equal and just society.

“I happen to completely agree with Patrick Harvie and strongly reject the neo-liberal argument that Nicola Sturgeon was making. That was the final straw.”

He said said the SNP’s support for NATO was a “problem” for him, adding that he did not support the Scottish Government’s policy on a single police force.

He added: “After 27 years, I thought ‘okay I’m off’. At the end of the day, I felt my political conscience comes first.”

Jim Sillars: I don't know if I will vote SNP in Brussels poll

A spokesperson for the Scottish Greens said: “Many SNP supporters know that their leadership’s attachment to tired, failed, neoliberal economics is not what we need to solve the climate crisis. Only the Scottish Greens’ plans for a Green New Deal offer the radical alternative to create jobs and a more equal society.”