Fès is the next stop on the Marrakech express

'Ballack, ballack," shouts a scruffy young boy as he smacks the rump of a ragged donkey struggling with a heavy load of dyed leather. "It means get out the way!" yells a trader from across the narrow medina street.

To avoid death by donkey I dive into a nearby butcher's shop where I'm greeted by a blood-stained man with a pointed beard and a wide smile who is removing hair from something ugly. "Welcome sir. You want to buy a goat's head?" he asks gleefully. The female customer next to me is hungrily eyeing bundles of trotters on the counter alongside other grotesque animal parts.

I tumble back out on to the street with such haste that I step on a man squatting in the gutter tending bunches of mint and coriander – he does not flinch. "It's your first time in Fès, I take it?" the trader quips, laughing at yet another overwhelmed tourist caught in the cultural headlights.

I spent many moments wondering if I'd unwittingly taken part in an elaborate time-travel experiment in the sprawling medina of Fès el-Bali, the old town. The ancient and spiritual capital of Morocco seems to be lingering somewhere in the Middle Ages, a multi-sensory feast of smells, tastes and sights.

Fès's ninth-century medina is the finest showcase of architecture in North Africa. It's the largest, most intact medieval city in the Arab world, recently declared a Unesco world heritage site, and has the globe's biggest car-free urban zone. So why is Fès largely ignored by British tourists while Marrakech continues to boom?

Although Fès is often preferred by visitors for its raw authenticity, Marrakech has been the more easily accessible option for travellers to Morocco. Until last year, GB Airways and Ryanair offered direct flights to Fès, but due to high airport taxes and limited interest, both airlines cancelled these routes. Consequently, travelling to Fès has been an arduous task, leaving the city in the tourism wilderness, usually considered as part of a longer journey around the country. It took me eight hours (including a stopover at Casablanca airport) to get here. But a new twice-weekly service from Gatwick to Fes, due to be launched by Atlas Blue in January, may change all that again.

It was barely daylight when I was snatched from my sleep by the day's first call to prayer. I gazed out the hotel window at the growing mêlée of locals preparing for the day ahead. The skyline was magnificent – madrasas, fondouks, palaces and mosques looked lustrous in the warm reflection of the morning sun.

The services of a local guide are essential in Fès, and after a traditional breakfast of strong coffee and warm Moroccan bread with honey I met mine. "Good morning, sir. My name is Mohammed Bouftila, but you must call me Momo," he said. Momo cut a dapper figure, sporting a perfectly groomed moustache and dressed in a white jellaba and bright yellow slippers. "Sorry, am I late?" I enquired. His smile broadened as he leaned towards me and whispered: "Those in a rush are already dead." I liked him.

"We will start the tour of my wonderful city at the heart of the medina," said Momo as we immersed ourselves in the bustle of the cobbled streets. Our progress was slow; at every 10 paces we stopped to speak to traders, exchanging medina gossip over offerings of mint tea until I could force no more of the sweet drink down me. But we finally reached our destination, the city's oldest building, the mausoleum of the city's founder, Moulay Idriss Zawiya, one of the most venerated pilgrimage spots in Morocco.

I stepped through the large wooden keyhole-shaped doors into the mausoleum's large entrance. "Unfortunately, it's forbidden to enter unless you're Muslim..." started Momo. I bounded back on to the street: tourists can only peek through the doors at the beautifully painted wooden arches and zellij (hand-cut polychrome tile) that adorn the vast walls inside.

Momo took me around the corner to somewhere I could take a closer look at, another architectural masterpiece, the 150-year-old palace Dar Glaoui, which non-Muslims are permitted to enter. "This was once the finest residence in Fès," announced Momo proudly as we approached the 17 sprawling buildings comprising houses, stables, a Koranic school and hammams.

Momo had told me earlier that "Fès's beauty lies on the inside", and Dar Glaoui proved a wonderful example of his point. From the street the palace looks innocuous, but on passing through the large cedar-wood doors a stunning oasis is revealed. It is the antithesis of the medina – beautiful courtyard gardens with lush green palms and sweet smelling bougainvillaea lead to large airy rooms with intricately mosaic-tiled fountains trickling with cool water. I whiled away a couple of hours wandering about the palatial rooms, enjoying the respite from the hot sun and madness of the medina, before returning to my hotel.

The trend for boutique hotels has swept across the Atlas Mountains from Marrakech to Fès, offering tourists intimate accommodation in the medina. My lodgings were at Riad Fès, a great example of how Moroccan traditions and contemporary style can blend effortlessly to provide luxury accommodation without harming Fès's rich architectural history. There is even an infinity pool in the courtyards. My room had all the comforts of a five-star hotel and antique features such as carved wood, ancient plastering and mosaic flooring to offer real character.

The following morning Momo was waiting for me in the lobby. "Are you ready for another day in the medina? I thought we'd do some shopping today." Market stalls selling everything from babouches (traditional leather slippers), embroidery, Berber jewellery and exotic carpets to Moroccan furniture line the narrow medina streets, with busy artisans in huts displaying their craftsmanship.

After a strong coffee at Café Kasbah – which has enviable views over the city's main gate on the tip of the medina's "shopping mile" – Momo suggested we visit Seffarine Square. The pretty tree-lined plaza is the site of the Seffarine Medersa, the oldest functioning Islamic school in Fès. It's also the place to find coppersmiths, who rhythmically beat sheets of metal into anything sellable. I spent a good hour bartering over a couscous pot I wasn't even sure I wanted, but the process was fun.

The rotting smell that exudes from the city's famous tanneries fills the nostrils wherever you are in Fès. The medina's largest tannery is situated on Tala'a Kabira and spreads across 20 medina rooftops. "Meet Lahkim. He will show you around," said Momo, introducing me to a slim man covered in muck. "I won't be joining you on this one. I'm allergic to the smell!"

Lahkim and I entered the slimy confines of the tannery. Skin and hide from sheep, goat, cow and camel lay on the ground spilling over with nasty indeterminable fluids. "The method we use is the same as our great-great-grandfathers used," explained Lahkim. "We scrape the skin until it's bare, then put it through a series of open-air lye and dye baths and after a good soaking, we place the leather on the rooftops to dry in the baking sun." The tannery is a gruelling dirty place from a bygone age and left me feeling a little queasy.

I could sense the amusement in Momo at my ordeal when we met up again. "Let's go for lunch," he sniggered. Lunch is considered the main meal in Morocco and Momo wanted me to try some Fassi cuisine. He took me to the family run Le Medina Restaurant where we were greeted warmly by the owner and shown to a large table surrounded by comfy cushions.

Plate after plate of food arrived – warm salads topped with marinated meats, spicy lentil broths, roasted aubergine and carrots drenched in olive oil, all served with warm bread. Then a sumptuous lamb stew called harira was served, filled with pulses, tomatoes, onions, parsley and coriander served with a fruity couscous.

Fès is a fantastically foreign place, an overwhelming city that quickly turns revelatory. But how long it will offer tourists an authentic Moroccan experience may lie in just how many more of us will now be encouraged to make the journey here.

Compact facts

How to get there:

Abercrombie & Kent (0845 618 2213; www.abercrombiekent.co.uk) offers four nights at Riad Fès from £862 per person, including return flights with Atlas Blue from Gatwick to Fès and B&B. A private guide is available for a full day from £68 per person.