The imposing, looming architecture of Christ Church can sometimes be a little forbidding but there’s a bowler-hatted brigade who aim to make it as welcoming as possible.

Founded in 1525, the college contains some of the most iconic buildings in the city, including the Cathedral, and as such attracts thousands of tourists every year, who are given the full treatment by a team of highly-trained staff.

Helen Dennett, from Kidlington, is one of them. However, in conversation the deputy head custodian could not contrast more with her austere surroundings, even though she is, traditionally, a part of them.

“Of course you stand out,” she says, “because we wear the bowler hats. So we’re immediately identified as being a part of Christ Church. We were originally known as the bulldogs but thank goodness we’re not now!”.

Warm and bubbly, Helen’s job satisfaction is clear even as she describes the minutiae of her day-to-day schedule. “Our main duty is to deal with tourists, so basically we’re the face of the college. If someone from Australia comes, we are the first people they meet, so we have to be jolly and smiley, which is not hard, especially on a day like today where it’s sunny and quite warm.”

Helen, 42, who worked in a news agency before becoming a custodian, is married with three children, Sharlene, 26, Steven, 20 and Chloe, 17, who works as a Saturday girl in Christ Church Cathedral’s shop.

Although Helen loves her job, when she goes on holiday with the family, she’s not exactly keen on sightseeing.

“There are too many tourists!” she says. “I live with it all year. I want to go to the middle of nowhere.”

Tourism is a large part of Christ Church’s success, with thousands of visitors every year. Still, Helen is quick to point out that Christ Church has a primary function.

“Stately homes are very different to what we deal with here, because we’re dealing with a live, living institution, that’s running all the time. So we’ve obviously always got students who live here, professors and dons who live here, and we’ve got the clergy that live here too, so it’s a constantly alive, breathing environment.”

Indeed, the venerable institution seems an odd and grand setting for student life, and considering the media stereotypes of Oxford excess, it’s surprising that Helen has encountered little in the way of bad behaviour on the part of its undergraduates.

“No, I can say honestly,” she says, “that I can’t recollect ever having seen anything that I would say was beyond reasonable behaviour. You hear stories, of course, but whether they’re true or not is another matter. Because you’re not there to witness it, you don’t know.”

In fact, she has more to say on the good relationships that are formed between students and custodians, many of which span the years.

“There’s a lot of students, so they need to get to know us initially. I arrived three years ago, so a lot of them are now leaving this year. It’s quite difficult actually, because you get to know them quite well. They come at 18 and they’re away from home, really, for the first time. I was quite sad to see them leave this year. But hopefully they’ll come back and tell us how they’ve done!”

Not that Helen need unduly worry – Christ Church graduates have a high record for success, with the college producing more prime ministers than any other Oxford college (13), and only two below Cambridge’s entire total.

I wonder if she ever sees the potential in the students she interacts with, and she is emphatic.

“Yes. Oh, definitely!” she insists. “Most definitely. Because there are some brilliant minds in here, but also they’re human beings as well and you look at them, and you think, could she be the next woman prime minister?”

This close relationship between the college’s custodians and its students came to the fore earlier this year when veteran custodian Bill Lewis retired after nearly 20 years.

“The last day he was here, it must have been between 50 to 70 students who clapped him out of Canterbury Gate,” she says. “They loved him to bits, and it was sad to see him retire.”

When asked if she envisions a similar career for herself, she considers his legacy more in terms of impressions than time served. “Well, I hope so! I really do. I hope that I do make people’s days, and that I give service to people.”

But Helen is also aware that the narrative of loyal service to Christ Church goes much further back than Bill, and she is happy to be a part of it.

“To be part of history? Absolutely brilliant, fantastic. Especially since I’ve always been very interested in history, even as a child. And the more you know, the more you can interact with other people. And that, quite simply, is our job.”

Interacting with people is clearly something Helen feels passionate about, and when I begin to ask what her favourite part of the job is, she cuts me off.

“Undoubtedly the best part is meeting people from all around the world. Amazing, and you hear so many stories.”

“We get people from everywhere. In fact, I’d say I’ve met people from at least 90 per cent of the countries in the world, and, it’s an honour.”

Helen’s plans for the future intend to take this on to another level, her latest project being behind-the-scenes tours that are now bookable online.

“It’s not just people who come over from the States or Australia or China who can book on,” she asserts, keen to encourage local people to make the trip. “I’d just really like to throw it out there and say ‘Come and see us!’ It’s a wonderful place. It’s part of the history of Oxford. We’ll welcome you in.”

No matter how her duties may change, however, it’s clear that for Helen her day-to-day job is its own reward, and a reward that she relishes. “Anybody who says to me that giving something to somebody is not a pleasure. . . Well, I wouldn’t say my mind, but clearly they’ve not done it very often, have they?”