It is said to offer a performance-enhancing pick-me-up for crucial Commons tests of mettle... or chemical consolation for those found wanting. But do MPs still need their supply of snuff?
Under a tradition sparked when smoking was banned in the chamber in the late 17th century, snuff, or powdered tobacco, is distributed on demand and free of charge to MPs.
Few partake nowadays, and for Green MP Caroline Lucas it has become an emblem of how Parliament remains tethered to a bygone era.
"As I walked into the chamber today, I noticed the snuff box still provided for MPs by the entrance," Ms Lucas reported in 2012, during a debate on reforming Commons working hours.
"I hope that members will take this opportunity to bring the Commons out of the snuff age and into the 21st century," she said.
The sight of the snuff box - fashioned from wood reclaimed from the old Commons chamber, which was destroyed in World War II, and decorated with a silver plaque - piqued another MP's curiosity, and he tabled a written question in Parliament on the topic.
Conservative MP for Gillingham and Rainham Rehman Chishti called on the House authorities to disclose how much snuff had been distributed to his colleagues in the past decade, and at what cost.
"It is unusual for members to request snuff, and there are no regular users of this facility. No records of usage or cost are maintained," came the response.
"Recent practice has been for this tradition to be maintained at the principal doorkeeper's personal expense."
Mr Chishti told the BBC: "Parliament is full of these quirky and anachronistic rituals and procedures.
"The last time this question was asked it was found that in 1989, 1.5 oz of snuff was being consumed at the cost of 99p.
"The answer to my recent question appears to show that no one's really using it, it's not paid for by the taxpayer and it's therefore not currently costing very much money."
Robin Fell, the current occupant of the principal doorkeeper post, described his snuff-distribution duties as a "great privilege" in a recent interview with BBC Parliament's Sam Francis - despite the apparent paucity of dabblers.
"It may come as a surprise to some people, as it does to some MPs, that I pay for the snuff," he said.
"A member may perhaps feel the need for a mild stimulant before he enters the chamber, or perhaps when he's leaving the chamber if he's had an unfortunate experience in there.
"But it's not a serious drain on my emoluments, because when I took over the job, my predecessor left me with a nice supply of snuff and I haven't had to replenish it yet.
"In due course, I suspect, perhaps next year, I might have to tootle off to a snuff shop, and purchase some."
Martin Dockrell, the director of policy and research at public health charity Ash, commented: "It seems a shame for the poor doorkeeper who has to shell out from his own pocket for MPs' snuff.
"But this tradition is a useful reminder of just how far things have changed. It used to be the sign of a good host to offer visitors tobacco and now it is the sign of a good guest not to smoke indoors - at least not without asking.
"It is, of course illegal to give free samples of tobacco products so organisations should be wary of following Parliament's example, unless they share the immunity of a royal palace."
There appears to be scant data on the health risks for non-smokers using nasal snuff, although an increased risk of cancer has recently been observed in smokers and ex-smokers who take the powder.
Public Health England notes that similar products, such as chewing tobacco, are "known to be carcinogenic", and advises "strongly against use of tobacco in any of its formulations, including snuff".
But Ms Lucas concluded that the Commons snuff supply was "perhaps just a faintly amusing anachronism, which falls into the category... of traditional things that are not harmful".
The principal doorkeeper puts it pithily: "If members want a pinch of snuff, why shouldn't they have a pinch of snuff?"