Jonny Hughes: Quangos have an important role to play

Yet, promises by incoming governments to slash the number and size of quangos usually results in campfire not bonfire – just look at Margaret Thatcher's and, more recently, David Cameron's thwarted attempts to emasculate the Forestry Commission.

These bodies were set up in the first place because ministers identified a need for them to exist, either to provide critical independent advice or to implement agreed legislation.

These two functions are difficult to deliver through the core civil service for a number of reasons. Advisory bodies are often internationally respected centres of expertise and provide well-researched evidence-based advice on which ministers can formulate robust policy.

When they are allowed to operate at arms length, which may not always be the case, they are good for democratic decision-making.

Their "critical friend" role can prevent ill-thought through ministerial hunches from becoming the failing policies of the future.

Arms-length bodies also operate outside immediate political timescales – they can take that longer-term view often missing from the daily political grind. They also work with and fund charities with similar aims, helping to get community action going.

My own organisation benefits from such a relationship with Scottish Natural Heritage, the arms-length body tasked with caring for Scotland's natural environment.

The critical friend role of arms-length bodies, and indeed the charitable sector, has never been so important.

As talented as some ministers in the SNP cabinet clearly are, they would be well-advised to draw on the expertise of their arms-length bodies when the Scottish Parliament cannot play the same checking and balancing role it did in its third session.

• Jonny Hughes is director of conservation at the Scottish Wildlife Trust