Police have both extra constraints and extra permissions - on the one hand, they can't dodge involvement in social disorder as the rest of us can and they may be required to conduct themselves privately in a way that does not undermine their public authority; on the other hand, they have permission to engage in deceptions, invasions of privacy and uses of force that are forbidden to the rest of us. But this does not put them beyond common morality.

I remember Stanley Benn remarking that one needed to be a certain age to engage with problems in political philosophy - I think he had in mind a certain breadth of understanding and experience - and so my political interests developed more slowly than the others.

The various roles we incorporate into the criminal justice system as well as the ways in which we construe such roles, lend themselves to the kind of ethical reflection that is open to us all. That said, once we have determined roles and their contours, those who act within them may have special duties and privileges that others may lack. Specific roles may generate ethical inquiries with novel forms, just as new technologies may push us in new directions.

The selection of topics for intensive research has often been a function of serendipitous opportunity. My forays into philosophy of education were largely in response to the prompting of friends and my dissatisfaction with much of what - at that time - passed for philosophy of education. I cannot honestly say that there has been either continuity or an overarching schema, though I suspect ,or at least hope, that someone who looked at my oeuvre might conclude that there was a philosophically integrated author.

In later years, when I started working in police ethics, I was professionally drawn back to the topic but as well was better able to see two sides to loyalty - its importance for certain central human relations such as friendships, but also its corruptibility in the sense that loyalty could be invoked against other moral constraints: it sometimes function as something of a moral Trojan horse, undermining other moral considerations.

Structurally I don't see a fundamental difference between what we may reasonably expect of police and doctors - though obviously the fact that doctors are generally pursuing life-saving activities and police may be engaged in life-threatening activities may lead to differences in how we construe the moral limits to their roles.

One of the real dangers of loyalty is that it may become associated with certain types of group-think, chauvinism, jingoism, and thus become socially destructive in ways that many other virtues are not likely to be when they are corrupted. Nationalism and patriotism are especially prone to misguided excess.