The position of a toilet paper roll may seem innocuous, but TP trustees have long been embroiled in a heated debate over the proper angle of the next square.

There are two types of people in the world: The “over” devotees who hang the roll so the on-deck wipe is facing the user, and the “under” fans who position it so it’s closer to the wall.

Thankfully, a professional has finally closed the book on the matter — a whopping 250 years since the hygiene tool’s invention.

Primrose Freestone, professor of clinical microbiology at the UK’s University of Leicester, says the somewhat counterintuitive “under” position is more hygienic and effective — despite the original 1800s patent showing the roll in the more natural-seeming “over” orientation, the Daily Mail reported.

“For the under position, there is less likely to be whole roll contamination,” Freestone argued.

That’s because “handling of the toilet roll from the over position” requires the user to employ two hands to extract a square after doing one’s business, per the microbiologist.

One hand is used to hold the roll in place so it doesn’t keep spinning forward and depositing too much paper, while the other takes the next segment.

On the other hand, the “under” method allows bathroom users to “pin the sheets against the toilet wall” and tear them off with the same mitt without “having to touch the exterior of the roll,” Freestone said.

By only using one hand to harvest a square, the odds of transferring hand bacteria to the toilet tissue and perhaps vice versa are reduced.

Meanwhile, using two hands increases the chances of spreading germs from one hand to the other.

Interestingly, Freestone’s theory is not shared by everyone.

Dr Christian Moro, an associate professor of health sciences and medicine at Bond University in Australia, claimed that the “under” method is the “hanging” offence as it ups the likelihood that the toilet user will “touch the wall behind when fishing for paper, leaving germs behind on that surface which can be spread to the next user.”

Coincidentally, studies show that 70 per cent of people still prefer it compared to 30 per cent in favour of the “under.”