Wendy Alexander insisted she would be "exonerated of any wrongdoing" over the illegal donation to her Labour leadership campaign fund.

Douglas Fraser on the latest SNP vs Labour row

Wendy Alexander insisted she would be "exonerated of any wrongdoing" over the illegal donation to her Labour leadership campaign fund.

Ms Alexander's comments came as further doubts were raised about when her campaign team first became aware that a donation from a Jersey-based businessman may have been impermissible.

Paul Green, a billionaire retail tycoon, gave £950 to Ms Alexander's fund, despite the fact that non-UK residents are barred under electoral law from making political donations.

The money was registered in the name of Glasgow-based Combined Property Services, but it was reported yesterday that that only happened after Ms Alexander's team realised the donation was impermissible.

The Electoral Commission has been investigating the matter for more than a month and it is understood it could publish its findings this week.

Speaking on the BBC's Politics Show yesterday, Ms Alexander said: "My campaign team accepted £950 that turned out to be impermissible.

"The moment we were aware of that we referred it to the Electoral Commission and I'm confident that I will be exonerated of any wrongdoing."

Ms Alexander again confirmed she had spoken to Prime Minister Gordon Brown and her brother Douglas Alexander, the International Development Secretary, after the row, but refused to be drawn on whether or not she had contemplated resigning as Scottish Labour leader.

Roseanna Cunningham, the SNP MSP for Perth, said Ms Alexander had "failed" to shed any more light on the issue.

She said: "Her refusal to deny discussing her resignation with Gordon Brown suggests Labour really do fear a domino effect and begs the question, who is in charge of Labour in Scotland?"