An analysis of the current make-up of the Scottish Parliament conducted by The Herald has uncovered a striking fact:

one-in-six MSPs has little or no experience of work life outside politics and public affairs. There remains a wide range of experience at Holyrood - with teachers and lawyers particularly well represented - but by far the most common former career for an MSP is politics. Many MSPs are, and have always been, professional politicians.

This has been a trend in the British political scene for many years now. All three of the leaders in the Commons for example have pretty much spent all their careers in politics and while the Scottish party leaders are drawn from non-political careers including teaching and law, the influence of the political professional at Holyrood has grown. At the beginning of the parliament's life, around 18% of MSPs were drawn from politics or other jobs traditionally leading to politics such as trade unionism but by 2011, that figure had increased to 28%.

This should be worrying for those who believe an ideal parliament is one that is broadly representative of the nation, although some caveats are required. Firstly, we should not assume that because the range of careers represented at parliament has narrowed, this means the parliaments of the past were more representative than they are now. In fact, the modern Commons is more representative than it was in the days when female MPs were rare and most Tories were drawn from the aristocracy.

Secondly, it should not be assumed an MP or MSP will necessarily be less in touch than someone who has run a business or worked in a so-called real job. Parliamentary democracy in the UK is based on politicians keeping in contact with the people they represent through surgeries and knocking doors when a vote looms; many modern politicians also regularly canvas opinion from their electorates.

Those caveats aside, the trend for people to come into politics more or less straight from university is one that needs scrutiny. Traditional professions such as law remain well-represented, but other sectors such as health, engineering and science - subjects right at the centre of political decision-making - are under-represented.

The danger of accepting this is politicians become increasingly alike and begin to think alike too, although part of the problem in changing this situation is that grassroots party membership has declined, thereby reducing one of the traditional recruiting grounds for politicians.

The idea of reserving quotas for politicians from certain backgrounds, as the Labour MP Denis MacShane has proposed, would be too prescriptive, but the challenge for the parties at Holyrood and Westminster is to find new, ambitious ways to encourage participation and recruitment from a broad cross-section of society. There is nothing wrong with someone dedicating their entire career to politics - there are many hard-working politicians who have done precisely that - but career politicians should form only one part of a healthy, representative parliament.