RUTH Davidson has been criticised for having double-jobbers in three of the most sensitive posts in the Scottish Conservatives.

Amid growing unhappiness over her judgment, party insiders have queried the multiple roles of her chairman David Mundell, her top spin doctor John McLellan, and the chair of her devolution commission, Lord Strathclyde.

Mundell was already the sole Conservative MP in Scotland and a Scotland Office minister when Davidson appointed him "interim" chairman when she became leader in November 2011.

The role was expected to last a few months until a full-time replacement was found. However, 18 months later, and after at least one Tory peer refused to take the chairman's job, the party has still failed to attract anyone better.

One Tory said having Mundell as MP, minister and chairman was "a ridiculous situation", adding: "We need a full-time chairman geeing up activists and improving our fortunes."

Besides being director of communications, McLellan also has an outside role as an academic at Stirling University. His alma mater appointed him an honorary professor in the department of film, media and journalism in 2010, and last September, three months after he started work for the Scottish Tories, he became a member of staff at Stirling with an "advisory and teaching role".

Both the university and the party have refused to say how much time McLellan spends teaching.

One Tory MSP said: "The thing about John is, no-one is quite sure what he does. I don't think he's explained it, and we're still waiting to see the fruits of his labours."

Davidson named Lord Strathclyde, the former leader of the House of Lords, as chair of her high-profile Constitutional Commission on extending devolution in March.

The following month he took up three jobs with multinational companies: commodity trader Trafigura, hedge fund manager Galena Asset Management, and the G3 Good Governance Group.

The commission has yet to set a date for its first meeting, and Strathclyde was absent from this weekend's Tory conference in Stirling.

"We need people in these roles giving it their full attention," said one senior Tory. "This calls into question their commitment to the job. And it's quite something that we still have an interim chairman so long after he was appointed."

A spokesman for the Scottish Conservatives said of McLellan: "John works well beyond his contracted hours for us and we have no issue with his working arrangements."