While there is little dispute regarding the nature of the world’s oldest profession, the second-oldest is still a matter of some debate.

Jonathan Sumption, a former justice of the UK’s Supreme Court, made the case for lawyers holding the world’s second-oldest job title while delivering this year’s Reith lectures for the BBC. But despite Sumption’s esteemed position, and the ancient history of dispute resolution, I wasn’t persuaded by his evidence.

Espionage is frequently held to have strong claims, the Book of Joshua telling us that: “Joshua the son of Nun sent out of Shittim two men to spy secretly, saying, Go view the land, even Jericho. And they went, and came into a harlot's house, named Rahab…”

The quotation not only supports an age-old case for spying, but it also refers to the fact that the first known spies lodged with someone engaged in the oldest profession of all.

Now I suspect that Joshua didn’t just come up with his plan while eating breakfast. Plots like this are developed over a drink. And fresh evidence was revealed this week regarding the ancient work of wine-makers.

Scientists have analysed the genetic code of grape seeds from 28 archaeological sites dating back more than 2,000 years.

They found that some of the seeds closely matched common wine-producing varieties that we still use today – such as Pinot Noir. It makes sense – why change something that’s worked perfectly well for several millennia.

But no sooner have we established that the provision of alcohol is an occupation as old as humanity, than another ancient vice comes to the fore.

Long before Conservative MPs smoked cannabis, the Chinese are believed to have puffed ganja at funerals in a period of history which the tabloids have labelled the ‘Stoned Age.'

News broke this week of an archaeological dig, this time deep in the Himalayas, where traces of THC (the psychoactive compound derived from marijuana) were discovered in wooden incense burners found within a tomb.

There is evidence however, that racehorse trainers have been around for just as long, if not longer, than any of the above.

The oldest text dedicated to the care and training of horses was written by Kikkuli of the land of Mittani in around 1300 BC. Having travelled from Mittani, on the banks of the Euphrates, Kikkuli worked in the service of the Hittite king Suppilulium – a royal patronage which has echoed, through the ages, all the way to the modern day.

Next week the world’s oldest professions will gather in the company of royalty for one of the world’s most celebrated events.

Lawyers, spies, prostitutes, drug dealers, purveyors of alcohol and racehorse trainers – they’ll all be at Royal Ascot, some probably more welcome than others.

I’m looking forward to seeing Laurens, trained in Middleham by Karl Burke and ridden by PJ McDonald, appear in the Queen Anne Stakes on Tuesday. But the selection for the weekend is for Austrian School, also ridden by PJ McDonald, at York this afternoon.