If Bosnians have the unofficial title of the world's worst Muslims, they surely have competition in Uzbekistan. Keeper of some of the Islamic world's holiest touchstones - the world's oldest Koran, the crypt of the Prophet Mohammed's cousin - it's a place where the sacred and secular mingle, with the secular far in the ascendancy.

Eighty-five per cent of Uzbekistan's population are Muslim, yet less than 5 per cent are said to practise their faith. Few women wear headscarves and only the old men seem to sport beards. The muezzin's call to prayer through loudspeakers was banned a decade ago after being deemed too noisy. And in the capital city, Tashkent, which was this year named a 'cultural capital of the Islamic world', it's far easier to find a bar than a mosque.

What you do find without any effort in Central Asia's largest city are the Soviet scars. When the city was flattened by an earthquake in 1966, Moscow rebuilt it to a colossal blueprint. Boulevards as wide as runways were laid down, lined with buildings both massive and monumental. A clockwork metro system was installed with stations as palatial as their counterparts in the Russian capital.

It's not until you visit the higgledy-piggledy old town that Islam floats to the city surface. Here, beyond the wiggling alleys, is Khast Imom, Tashkent's Islamic heart, where madrassas (Islamic schools) ring a small library housing the Osman, the world's oldest Koran, said to have been written just two decades after the death of the Prophet in the 7th century.

It's at Khast Imom that I'm treated to my first views of the turquoise tile-work that adorns mosques and madrassas across Uzbekistan. The very image of the country, they're as exquisite as Pompeii's mosaics. It's in the west of the country that such images become commonplace, in cities whose names evoke the heyday of the Silk Road: Samarkand, Khiva, Bukhara. And it's here we head for the next morning, flying over the desert to Khiva, the most westerly of the cities.

We've arrived on Independence Day, the national holiday celebrating the country's release from Soviet rule. Thousands of people are out in their finery, crowding the stunning old town, which seems unnaturally clean for a place built largely of mud. Stalls line every lane, selling everything from Cossack hats to wolf pelts, and there's the chance to be photographed with a slew of teddy bears.

Almost Dalmatian in its labyrinthine design, the old town's 24 cluttered hectares once housed 64 madrassas and 92 mosques. Every building is a history text unto itself (and almost every madrassa now a museum), though two minarets - one tall and one small - dominate the scene. At 56 metres, lighthouse-lookalike Islom-Huja is the tallest minaret in the country, while squat Kalta Minor is a vision of what might have been. Studies suggest if it had been finished it would have stood 195 metres high, making it perhaps the tallest building in the world at the time.

Independence Day slides into Independence Night and the party moves outside the town walls. Tyres squeal late into the night, car horns blare and a fist fight entertains hundreds of Khiva's youths. It's just another day in which the Uzbeks seem happier to play than pray. The next morning we begin our journey east towards Bukhara, driving through the Kyzyl Kum Desert, where the roads are as patchy as the vegetation. People live their whole lives here, yet nine hours on a bus feels too long.

Bukhara's medieval statistics are even more impressive than Khiva's, with the old town once supporting more than 100 madrassas and 300 mosques. Known universally as Central Asia's holiest city, it's a sacred place where, equally, nothing seems sacred.

Walk through the door of any former madrassa and you're likely to find souvenir stores filling the students' cells. In an excavated temple six metres below the surface of the city, there are carpets for sale. From a roadside bar one evening I hear the futile voice of a muezzin struggling to make his call heard over the ruckus of the bar. If only he had a loudspeaker! And yet, somehow, in Bukhara, this all feels right, for religion and retail have been bedfellows here for centuries.

A main stop along the Silk Road, the city was famed for its covered bazaars. Three survive, making this the one Uzbek city where shopping is as much a feature as the architecture and history.

If one place epitomises the Silk Road even more than Bukhara it's Samarkand, my final stop in Uzbekistan. Conversely, if one city has stepped out from the shadow of its time capsule it's also Samarkand, which has the most lived-in feel of the any of the cities.

The shined and buffed old towns of Khiva and Bukhara can feel a little precious, but nothing about Samarkand is preserved in aspic. It might have the country's finest monuments, but it's a breathing, heaving city swirling around the nucleus of the Registan, Uzbekistan's most awesome sight. Pinned to the ground by a trio of enormous madrassas (the entrance arches alone are 15 metres high), this plaza is precisely what has drawn me to Uzbekistan, an image as iconic in its own way as the Eiffel Tower or the Taj Mahal. Each tiled facade is an elaborate, mesmerising jigsaw puzzle, though inside the buildings more resemble shopping malls than madrassas.

More so even than in Bukhara, souvenirs fill every doorway, and there's not a single room that serves as a museum or information centre. If it seemed right in Bukhara, it somehow feels wrong here. If the Registan disappoints me, however, little else about Samarkand does. Despite its growing popularity, it remains a city where people still stop you simply to say hello and practise their English. A man photographs me with each of his four children then invites me to stay the night in their home. Muslim women clutch my arm as they're photographed beside me. One afternoon, our group trails through the tombs at Shahr-i-Zindah and into the crypt of the Prophet's cousin, Qusam ibn-Abbas. 'This place is like Mecca to us,' Shuhrat says, yet we seem to be breaking all the rules. We haven't removed our shoes and the women's heads are uncovered. 'Nobody minds,' Shuhrat assures us, 'this is a tourist town.'

Later, as I wander past a mosque, a mullah waves me inside. 'Are you Muslim?' he asks. I shake my head and he recites a few Arabic phrases, asking me to repeat them. Finished, he slaps me on the leg and roars with laughter. 'Now you are Muslim,' he says, though in Uzbekistan I'm no longer certain what that means.