AN independence group hoping to increase pro-Yes seats in the Scottish Parliament at next year's election is being backed by another former SNP politician, it has emerged.

John Wilson pledged support for the new Alliance for Independence campaign, spearheaded by former SNP MSP Dave Thompson, after seeing so many "wasted" votes on Holyrood's two-tier voting system.

Wilson was an MSP under Alex Salmond from 2007 in the Central Scotland region but left the SNP after the 2014 referendum and sat as an independent MSP until 2016. He stood unsuccessfully as a Green candidate in the Coatbridge and Chryston constituency at the 2016 Scottish Parliament election and then as an independent candidate in the 2017 Scottish local elections.

Polls suggest the SNP are likely to clear up in the first-past-the-post constituencies again next May, which could leave the party with only a handful of proportionately elected regional seats.

READ MORE: Dave Thompson defends new Alliance for Independence party

Wilson told the Record: "In 2016, the overwhelming majority of second SNP votes produced little or nothing for the independence movement. In Central, the SNP took every seat and the second vote became a wasted vote."

He continued: "I don't think it causes confusion. My view is voters are looking to maximise their vote, they're the ones who want to drive home the argument for independence. Quite rightly AFI won't stand constituency candidates because they understand the SNP will want to field them everywhere.

"This is an opportunity for other political figures to be involved. The reality is we need to get as many MSPs to show there is a clear majority in 2021 that indicates Scotland’s desire for independence."

Wilson said he is happy to offer support at this stage and no decision has been taken on whether to stand on the list. He suggested a single-issue independence party would be more likely to attract SNP voters on the regional list.

READ MORE: Nicola Sturgeon urges ‘both votes SNP’ to win Holyrood majority in 2021

Thompson, an MSP between 2007 and 2016, believes SNP voters could add as many as 24 pro-indy MSPs by lending their vote to his single-issue outfit.

Discussion is ongoing among some in the SNP about the merits or not of a second independence party fielding candidates next year.

The Scottish Government's Constitutional Affairs Secretary Michael Russell said Thompson is "mistaken" in his analysis. MP Kenny MacAskill, a former justice secretary, said voters shouldn't waste their second vote on the SNP but should back another independence option.

In an interview over the weekend First Minister Nicola Sturgeon said she would be calling for voters to back the SNP on both the constituency and regional parts of the Holyrood ballot next May.