It follows research by the Jimmy Reid Foundation that found the 70% of the population who earn less than £24,000 make up just 3% of those who give evidence to Holyrood committees and only 11% of those appointed to public bodies.

The findings, supported by the Joseph Rowntree Reform Trust, found that, in contrast, the 13% of the population earning more than £34,000 made up 67% of those giving evidence to committees and 71% of those appointed to public bodies.

The creation of the Commission on Fair Access to Political Influence has won cross-party support. SNP MSP Jamie Hepburn said: "The findings starkly demonstrate that more has to be done towards involving a wider range of people. Any recommendations that can be made as to how to achieve that will be welcome."

Labour MSP Neil Findlay said: "Sadly I am not surprised by these figures. Whether it is in public appointments, through evidence sessions, in employment or through those who access people in power through lobbying, the parliament appears to entrench rather than challenge the view that it works in the interest of a small few."