I HAD BEEN an informer for over a decade when I finally learned what the job entailed.

There were no surprises. I knew how society viewed us: lowborn hangers-on, upstarts too impatient for honest careers, or corrupt nobles. The lowest grade was proudly occupied by me, Marcus Didius Falco, son of the utterly plebeian rogue Didius Favonius, heir to nothing and possessing only nobodies for ancestors. My most famous colleagues worked in the Senate and were themselves senators. In popular thought we were all parasites, bent on destroying respectable men.

I knew how it worked at street level – a hotch-potch of petty investigative jobs, all ill-paid and despised, a career that was often dangerous too. I was about to see the glorious truth of informing senatorial-style. In the late summer of the year that I returned with my family from my British trip, I worked with Paccius Africanus and Silius Italicus, two famous informers at the top of their trade; some of you may have heard of them. Legals. That is to say, these noble persons made criminal accusations, most of which were just about viable, argued without blatant lies and supported by some evidence, with a view to condemning fellow senators and then snatching huge proportions of their doomed colleagues' rich estates. The law, ever fair, makes decent compensation for selfless application to demeaning work. Justice has a price. In the informing community the price is at least twenty-five per cent; that is twenty-five per cent of all the condemned man's seaside villas, city property, farms, and other investment holdings. In abuse of office or treason cases, the Emperor may intervene; he can bestow a larger reward package, much larger sometimes. Since the minimum estate of a senator is a million sesterces – and that's poverty for the elite – this can be a nice number of town houses and olive groves.