When did the Nigerian advance fee email scam (aka “419 fraud”) first appear? Nobody can say for certain. In Internet time, it probably goes back to the mid-1990s, in letter form, perhaps as far as the 1970s.

In the earliest days, it perhaps sponged on a small banana leaf of plausibility. Nigeria - and West Africa in general - was rich in oil and therefore rich, was hard to do business in, and corrupt enough for people to look for alternatives ways of moving money.

Remarkably it is still with us in a more hardened age, clinging on as ferociously as does its close cousin, the “you have won the lottery fraud.” By 11.08am on September 5th, the database of urgentmessage.org, a site that tracks examples of 419s, had already received 20 different letters for that day.

You’d imagine it should be dying out by now, but think again. The letters wouldn’t exist it nobody – however few in number - replied. That doesn’t mean anyone has the foggiest idea how many people are snared by 419s.

Searching for an explanation as to why people fall for it, you end up with the old and rather unsatisfactory idea that humans tend to be “highly suggestible”, a polite way of saying that some people are naïve or plain stupid. That’s comforting because it implies that the rest of us are not.

As the first great email scam, the 419s blazed a trail that told criminals something they might not otherwise have believed. Conning people can be easy.