Midway through my year 13 at high school, a newcomer joined the class. Graham‘s family had been living on the Spanish Costa del Sol, from where he travelled to Gibraltar to attend school, back and forth across the Spanish frontier every day. The Franco regime was determined to force a confrontation with Britain, and the daily commute had become an epic. Graham‘s passport filled up with stamps every few months. I was fascinated, but understandably the novelty had long since faded for him and his parents. A few years on, I began to plan that first big overseas jaunt, and Graham obligingly jotted down one or two contacts. The little green address book and I never quite made it to Gibraltar. Bound for Morocco early this year, I found myself again in Algeciras, the bustling ferry port which funnels human and cargo traffic across the narrow straits separating Europe and North Africa, bridging the chasm between the First World and the Third. Signs in three languages identify every second shopfront as a ticket agency. Lured by the monolith across the water, I put Morocco on hold and rode the bus back around the Bah铆a de Algeciras to La L铆nea, the border town huddled on the isthmus below the rock. The rock towers over the twin towns clutching at its skirts, a colossal sugarloaf of limestone. Under a ragged green thatch, its heart is riddled with natural caves and man­made passages. A short trot down La L铆nea‘s main avenue... and the Union Jack was fluttering in the breeze. A bobby in helmet and reflective yellow jacket stood joking with his green­uniformed Guardia Civil counterpart. Even the public notices had that menacingly polite English manner...

Once through the border gate, the road ­ Winston Churchill Avenue, of course ­ crosses Gibraltar‘s airstrip, built onto reclaimed land. This pimple on the tail of Iberia is an enclave of England, complete with cosy pubs where drinkers tuck into a pint of Bass or barrack for Manchester United... even if they drive on the right and converse in a peculiar patois. Sterling circulates, mixed with a sprinkling of distinctively Gibraltarian coins and notes.

The euro is almost equally welcome, too.Saxon, blending Spanish, Genoese, Jewish and British strains. On Saturday night the Jewish community sets out on their Sabbath promenade, the men in suits and skull cap, the women in frock coats and fancy hats, strolling blithely past Muslim Moroccan guestworkers in hooded jellabiya.

Gulls squawked incessantly as I tramped around the upper reaches of the rock. From the Upper Rock Nature Reserve, the view extends out over the straits to the Rif Mountains of Morocco. Taped orchestral music was playing inside St Michael‘s Cave, and banks of chairs lay stacked either side of a sizeable stalagmite. The cave boasts a recorded history going back to AD45, when it was feared as the Gates of Hades, a yawning orifice in this Pillar of Hercules. Now it serves as a superlative natural concert hall.

The famous tail­less Barbary apes were never far away, baring their buttocks, grooming one another‘s marmalade pelts, or jumping through car windows to seize titbits.

At intervals one notices giant steel rings embedded in the rock faces, put there to help haul cannon up from sea level. During a three­year siege in the 18th century, British Army engineers gouged out tunnels so they could install guns to fire down on the besieging Spanish forces. This, the Great Siege, was just one of 14 which Gibraltar has weathered. The Great Siege tunnels have become one of several visitor attractions maintained by a local administration that seems determined to safeguard Gibraltar‘s identity in the face of London‘s indifference.

Gibraltar has always been a garrison town. Names like Ragged Staff Gates, Couvreport Battery and Kings Lines Battery are proudly inscribed in black and white paint. Beside the Southport Gates, Trafalgar Cemetery is closely linked with Nelson‘s great naval victory of 1805.

From halfway up the rock, Gibraltar reveals itself as a bustling port. High­rise apartment blocks climb the slopes, some reached more readily by stairs than by the narrow, winding roads. Only a privileged few stretch their legs in the Victorian­era detached houses with private gardens, high on the upper slopes.

Above the town stands the Tower of Homage, built in 711 by the Moorish chief Tariq Ibn Zeyid, whose name has been immortalised as Jebel Tariq, Tariq Mountain. It is a formidable square fortress, a testimony to the strategic and architectural skills of the warriors who conquered southern Spain.

The Castle Steps lead down through crowded tenements where urchins call in Spanish and Arabic, to Cannon Lane and Main Street. Many poky little grocery stores and tax­free liquor outlets are owned by Indians, while merchant banks shelter behind brass plates.

Gibraltar‘s Alameda Botanic Gardens tumble down the slope towards the cable car station, overlooked by the great white bulk of the Rock Hotel, clearly a hostelry of some style. In the gardens is a statue of Molly Bloom, the heroine of James Joyce‘s Ulysses, inscribed with Molly‘s versified reminiscences of her salad days in Gibraltar:In the morning, Gibraltar‘s fragmentary bus service deposited me at the absolute end of the line, the red and white 1840s lighthouse at Europa Point. A tatty convenience store announced itself as the Last Shop in Europe and offered Much Cheapness. More uplifting was the large, Saudi­funded mosque nearby. It represents not just a place of worship for a few thousand emigre Moroccans but a renewed Islamic toehold on the Iberian Peninsula, fraught with symbolism.On the other side of the town, Gibraltarians displayed an ethos more Mediterranean than British as families sprawled across the flagstones of Casemates Square. It was mid­January, and just warm enough to enjoy sitting outdoors. From here the Landport tunnel, rebuilt in 1729, was once the only land access to Gibraltar.

Almost at the airstrip, a street sign caught my eye. Lined with blocks of flats and car accessory shops ­ quite unremarkable, in spite of its evocative name ­ Devil‘s Tower Road immediately conjured up Graham‘s entries in my old address book.

That night in La Linea I watched the year 2001 in review on Gibraltar television. During some months the biggest news had been the dog show or the retirement of a long­serving priest. Spanish cigarette smugglers received their just desserts and a dinghy laden with Moroccan illegals was intercepted. Next morning in the plaza an athletics carnival got underway. Teams had arrived from Gibraltar and from Ceuta, a Spanish enclave on African soil whose existence seems to suggest something of a double standard. Nearby, the ubiquitous golden arches materialised to provide food for thought... what do such man­made frontiers really mean in the era of the global economy¬