It is tempting to imagine that in our increasingly secular society, sectarianism must be in rapid and terminal decline, an anachronistic throwback kept alive artificially by the tribalism of certain subgroups of rival football fans.

Sadly, that is not so. Last month, official figures show there were 876 religiously aggravated offences in Scotland in 2011-12, up one-quarter on the previous year, with fewer than one-third of all offences football-related.

The sheer number of incidents may be explained in part by greater awareness, reporting and recording of the offences. Yet the figures also reflect the fact that sectarian bigotry in Scottish society simply refuses to wither and die.

In The Herald today, Duncan Morrow, who leads an expert group advising Scottish ministers on sectarianism in 21st-century Scotland, delivers something of a wake-up call. Highlighting frequent claims of "an embedded anti-Catholicism" persisting in Scotland, he states that sectarianism is not just a "ned issue", a street culture phenomenon played out by angry young men, but is part of Scottish society as a whole, including the suburbs and polite society.

This should not – and for many, will not – come as a surprise. After all, alongside the trading of plain insults, sectarian bigotry has, like any kind of prejudice, a more insidious side. In some Scottish communities it is entangled for historical reasons with class or with perceived cultural differences. Thus, warns Dr Morrow, it has become a way of defining who is part of the tribe and who is not.

It is no wonder, in view of this, that the task of defining sectarianism and its impact is so difficult and daunting to policymakers. The issue is further complicated by the fact that different individuals living in Scotland, even individuals in the same community, can have strikingly different experiences of sectarianism, some regarding it as a peripheral problem at worst while others experience it as a persistent blight. The positive experience of one, however, does not cancel out the negative of the other. The debate must move beyond the trading of tit-for-tat anecdotal evidence if policymakers wish to get to grips with the issue and make a real difference.

Dr Morrow is absolutely right to counsel against the unhelpful influence of those on the extremes of the debate, either those who refuse to accept the problem exists beyond the football terraces or those who make allegations of sectarianism without evidence, springing from a sense of victimhood. What is clear is that a frank and open debate about the ways in which sectarianism manifests itself in wider society is overdue.

The work of the advisory group is therefore welcome and necessary. It remains to be seen what policy initiatives might flow from it. Dr Morrow looks favourably on shared school campuses and certainly they have been judged as successful by most staff and parents where they have been introduced. However, a focus on education should not be allowed to deflect attention away from the fact that bigotry is typically learned and ingrained in the wider community and indeed, in the home.

If the Scottish Government and society are to tackle this problem, it is essential that it fully deconstructed understood first. Difficult questions about the impact of bigotry on broader Scottish society cannot be ignored.