An SNP MP has refused to say if he is still using taxpayers' money to employ an activist who stood down as an election candidate amid a benefit fraud probe.

Graham Leadbitter, the SNP’s energy and net zero spokesman at Westminster, has stonewalled repeated requests for confirmation of whether he still employs Sally Donald, who once boasted about riding the SNP ‘gravy bus’, as his head office.

She stood down as the SNP candidate for Edinburgh Southern last month after it was revealed she was the subject of a Social Security Scotland investigation into her claims for adult disability payment.

It has been subsequently reported by the Scotsman newspaper that she is liable to pay back more than £19,000, although she has ‘strenuously’ denied any and all wrongdoing.

The latest register of interests of MP staff, published on March 23 – nearly three weeks after Ms Donald quit as an SNP candidate – still lists her as a member of staff for Mr Leadbitter, the MP for Moray West, Nairn and Strathspey.

Mr Leadbitter refused to respond to multiple requests for confirmation of whether she had been removed from her role, while the SNP’s Westminster press office and party headquarters also failed to provide an answer on whether she remained his taxpayer-funded employee.

When contacted via her parliamentary email address, an automatic reply said Ms Donald was ‘currently out of office’ and urgent queries should be directed to Mr Leadbitter, ‘otherwise I will respond on my return’.

Scottish Conservative social security spokesman Alexander Stewart said: ‘Graham Leadbitter must come clean on whether he is still using taxpayers' cash to employ Sally Donald.

‘Sally Donald resigned in disgrace as an SNP candidate after her behaviour was reported to the benefits quango and leaked to the media by someone inside her party.

‘Hard-working, over-taxed Scots have a right to know whether or not public money is being spent by the Nationalists to employ an individual that they have deemed unfit to represent them in parliament.’

At an event in Glasgow on Monday, Scottish Conservative leader Russell Findlay highlighted the case as he said the Tories are the only party being honest about the need to curb the SNP’s ‘out of control’ benefits bill.

He said: ‘Hard-working Scots are sick of being hit with sky-high SNP taxes only for John Swinney to spend their cash on his out-of-control benefits bill.

‘The SNP's light-touch benefits system has created a charter for chancers like Sally Donald who lived an Instagram lifestyle while pocketing thousands of pounds she wasn't entitled to.

‘Our common-sense plan to reduce the benefits bill will deliver fairness for taxpayers while ensuring support for those in genuine need. We're the only party being honest with Scots that our country cannot afford the SNP's ballooning social security spending.’