When my sister came to visit me in England last spring, there were a handful of authentic Oxford experiences I wanted to ensure she had - going punting, attending a college bop, making a late-night stop at the kebab van after a long bout of drinking.

Though the last-mentioned may not be what one thinks of when evoking the traditional culture of Oxford - you mean Tolkien didn't snack on chicken kebabs from the Hot n' Tasty van during his time here? - they are as salient a part of the Oxford landscape as Tom Tower or the Rad Cam.

Really, how can you miss them? After dark, the vans suddenly pop up, one by one, as if from thin air. Before long, they are lining the streets of Oxford luring unsuspecting nightime wanderers with the irresistible scent of frying grease. As the sun rises, they're gone.

Every person has their own strong opinions on the preferred van and menu item of choice. Some tell me the chicken kebab with hoummus is best, others swear by the chips.

There is a distinct geographical component, meanwhile, to van loyalty. Kebab Kid even has a Worcester special for that college's students. Green kids have their own van, and so do Christ Church's.

I find the kebab van phenomenon a bit mystifying. Hot food being sold out of a vehicle? And not just any food, kebabs, of all things? Not that Americans don't have our own late-night snacking habits. Indeed, every city I've lived in has its own custom.

In Los Angeles, it was Mel's Diner on Sunset Boulevard. In Washington DC, it was the aptly-named The Diner.

The thing about all these locales, though, was that you could find restaurants hawking their delicacies at all hours of day and night. In Oxford, in contrast, the entire city (minus bars) shuts down around 10pm. There is no food to be had anywhere. What is a student - the ultimate night owl - to do?

Some savvy entrepreneur with an old van realised this and before long, the kebab van age was born.

So are the kebab vans solely a last resort for drunken students, with nowhere else to turn for nourishment? Or is there something particularly alluring about the kebab itself?

I opted to go to the source: the kebab van itself. And in my mind, there is only one van, McCoy's, parked, ever so strategically, outside the entrance to my college.

Looking for 'McCoy', I found instead Jamshaid, the van's loquacious owner, who assured me that their clientele was not dominated by boozy Oxford matriculants.

Rather, he served a mix of locals - taxi drivers, policemen, families - in addition to my own peers. "We're an established van. We're well known. We get lots of regulars," he added.

Indeed, the van has been in business for 21 years, started by a Scotsman - the Real McCoy - and sold to Jamshaid several years back.

So why kebabs? "They're filling, quick and easy to eat," he said. "And they're a tradition in Oxford."

Well, there you have it. Tour guides, add a stop to your routes - on your left, the Bodleian, on your right, the kebab van.