THE SNP is facing calls to reveal exactly what it knew about concerns over discrepancies in the finances of a pro-independence group, which led to an MP stepping down from the party.

Natalie McGarry, the Glasgow East MP, resigned the SNP party whip on Tuesday after she became embroiled in a scandal involving Women for Independence, the campaign organisation she co-founded and for which she looked after the finances.

Police were called in by the group on Sunday after alleged discrepancies were uncovered in its accounts, with the focus believed to be on an online PayPal account which was linked to Ms McGarry's own bank account.

Around £30,000 is said to be unaccounted for, after an internal audit earlier this year uncovered apparent discrepancies between income through donations and expenditure. Ms McGarry has denied any wrongdoing.

The SNP has admitted that it has known about potential issues surrounding the group's finances "for a few weeks" before Women for Independence went public at the weekend. However, it has denied that it knew the detail of the allegations, a claim that has been questioned by opposition parties given the close links between Women for Independence and the SNP.

Seven of the 20 Women for Independence national committee members who put their names to a statement revealing apparent financial irregularities are SNP candidates at the upcoming Holyrood elections.

Jackie Baillie, Labour's public services spokeswoman, called for full transparency from the SNP over who knew what about the case, and when.

She added: "Nicola Sturgeon said she needed more detail before acting but later in the day the SNP admitted it had been aware of this case for several weeks.

"Natalie McGarry is an SNP MP and seven of the national committee members of Women for Independence are SNP candidates for next year's election. We now need to know when concerns were first raised with SNP officials, including chief executive Peter Murrell, and what action was taken - if any.

"The public also deserve to know when the SNP candidates and Women for Independence national committee members first became aware of these allegations and what action they took to communicate them to SNP officials and Nicola Sturgeon."

The SNP also faced calls to tighten up its vetting procedures, after Ms McGarry became the second MP within two months to resign the party whip with Michelle Thomson stepping down in September following questions over property deals. Bill Walker, the former SNP MSP, was jailed for domestic abuse in 2013.

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Scottish Conservative deputy leader Jackson Carlaw said: "There have now been three SNP parliamentarians who’ve been at the centre of police investigations in recent times.

"These three episodes have exposed SNP vetting procedures for its parliamentarians as shambolic and inadequate. The clear responsibility for this lies with the leadership of the SNP."

The controversy over Ms McGarry is expected to dominate at First Ministers' Questions today. Ms McGarry's aunt, Presiding Officer Tricia Marwick, will carry out her duties as normal.

A spokeswoman for the SNP said: "Women for Independence is an entirely separate organisation and we have no role in their financial arrangements. We received no detailed information about the allegations made to the police and no documentary evidence in relation to this matter from Women for Independence at any point prior to – or since – their public statement."