Sinister goings-on can lurk in even the most respectable places. From my office window, I can see a plain mews building. It has apparently been a high-class brothel for decades. You wouldn’t know it from the daytime activity – only at night is there telltale behaviour hinting at its true commercial function.

Meanwhile, round the corner a ground floor flat has been illegally converted into an industrial kitchen, making stock for ethnic restaurants. It is staffed entirely by immigrants. I have a suspicion, perhaps unfounded, that not all of them carry wholly legitimate work visas. And very close by there is an everyday pub, outside of which on a Friday night young men deal in ecstasy tablets and other recreational drugs. At weekends, in a street market not far away, there are stalls selling all manner of counterfeit and pirated products, from toiletries to DVDs.

If you look with a cynical eye, in every town and city there are hundreds and possibly thousands of criminal enterprises, run by entrepreneurs who are oblivious to the law. Most are small-time and relatively makeshift, but some are substantial and well established. Many feed an appetite for various vices; while other crooked firms may provide legal products, but only by breaking tax, planning, immigration and other laws. These are the outlaw elements of the business world, and their revenues run into the billions.