Rua da Republica must have looked splendid in its heyday. Laden carts must have rolled along its easy width. Well-dressed ladies must have strolled its pavements. The sound of laughter and conversation must have ebbed from between the doors of its elegant houses.
But no more. My only obvious companion as I cross the defunct doorstep of one such mansion is a tiny grey lizard. Startled by my arrival, it skitters over the broken tiles of what was the hall, and hides under a bush that is growing in the corner.
Two centuries ago, this was the residence of a wealthy merchant. Now it is a shell, eaten by neglect and sea salt. The roof is a memory, the walls fatally wounded, holes in their fabric gaping to reveal the Indian Ocean behind. And while there are traces of former magnificence – not least the red and white patterns on what is left of the plaster – their only observers are the grasshoppers that skip blithely over the faded lines and loops.
Nor is this a lone example. Rua da Republica's once prosperous smile is now a down-turned mouth of cracked teeth and forlorn gaps, all dust, dirt and decay – a stark reminder of what happened when the tide of history turned in the 20th century, and the furthest extremities of European imperialism were left marooned in distant countries.
This is Ibo. Nowadays it is a small outpost off the coast of northern Mozambique, one of more than 30 islands that make up the Quirimbas Archipelago. But at its height, in the 18th and 19th centuries, it was one of Portugal's key bases in south-east Africa. And although never as important as its sister island Ilha de Mocambique – the European power's nerve centre in the Indian Ocean 200 miles to the south – it was a hotspot of cash and influence, home to 37,000 – an enclave built on gold, ivory and the unslakable thirst of the slave trade.
My first glimpse of Ibo is the rudimentary grass airstrip on which I land, with something of a thud, after a 20-minute flight from the mainland city of Pemba. But its dilapidated beauty is instantly apparent: the whitewashed flanks of the church of Sao Joao Baptista; the smooth curve of a forgotten promenade on the west edge of the old town, where circular cavities in the walkway mourn the flowerpots they once held; and the streets, which have names such as Rua do Matadouro and Rua da Fortaleza, out of synch and out of time in this young African republic. Beyond lies the imposing bulk of the Forte de Sao Joao, where Portuguese cannons still guard against Dutch incursion and a room off the main courtyard is stuffed with torn folders of administrative records – groaning shelves of council minutes and school appointments, dumped here after the collapse of colonial rule.
Portugal held sway on this stretch of the globe for five centuries, almost from the moment Vasco Da Gama passed the Cape of Good Hope on his world-changing voyage of 1497-98. But this lost library is proof that, when the end came for colonial Ibo, it came quickly. In April 1974, the Carnation Revolution in Lisbon overthrew the dictatorship that had run Portugal since 1926. The new government promptly relaxed its grip on the country's overseas "possessions". Within 14 months, Mozambique was independent – and expats fled for Europe, including those who had dwelled in comfort on Ibo.
Yet the island is no deserted Marie Celeste. On my first morning, I stand on the ramparts of Fortim de Sao Jose, Ibo's second, lesser fort, and watch children performing back-flips on the beach. Giggling and guffawing, they are having fun – mainly because they are playing truant. They should be at school in the village that spreads out north of the old town, where Ibo's indigenous population ekes out an existence from fishing.
But, while the locals go about their business amid the ruins – the main jetty is still behind Rua da Republica – there is no curiosity about these structures, symbols of a regime that once dominated and subordinated. People are busy here, and Mozambique one of the poorest nations on the planet. The fate of a few colonial buildings is of no note.
In fact, for all the length of Portugal's stay in Mozambique, it is another culture whose imprint is discernible on Ibo's modern inhabitants. When Da Gama reached the region, he found that Omani traders, sailing south, had already made their mark. It is still there – in the salwar kameez (albeit a beaded, African version) worn by many Ibo men; in the eight mosques – squat, basic, but sites of worship nonetheless – in the village; in the local language Kimwani, which, though indebted to Swahili, has Arabic in its DNA. I soon discover that the predominant greeting is not, as had I expected, the Portuguese bom dia, but salama – a sibling of the Arabic as-salam alaykum ("peace be with you").
Perhaps it is this cultural chasm that explains the state of Ibo's most desolate landmark. On the road in from the airstrip, on a patch of rocky ground, lies a cemetery. Crumbling and abandoned, its walls curled over, its chapel of rest open to the sky, it is a place of death in every sense. Insects click and flutter on the baked headstones.
Yet not all of colonial Ibo is being left to rot. The island is under consideration for Unesco status, while tourist interest is increasing as Mozambique – for so long a no-go zone due to the civil war that tore it apart from 1977 to 1992 – begins to appear on the travel radar. And, slowly and sporadically, restoration work is under way – an effort that has seen a clutch of buildings repaired to something approaching their original condition.
One of these is the Ibo Island Lodge, a hotel that has been slotted into what was the home of the governor of the Nyassa Company, an Anglo-French trade group that controlled the Quirimbas, under Portuguese charter, between 1891 and 1929. With pink bougainvillea swarming over its fence, there are still echoes of colonial pomp to its wood beams, high ceilings, long veranda – and west-facing roof-terrace restaurant. Here, on three warm evenings, I enjoy the embers of the day over a cocktail and ponder that, just as the sun will set again tomorrow, so this coralstone Pompeii will surely rise as a destination.
You can fly to Pemba, via Johannesburg on South African Airways, or via Nairobi on Kenya Airways. British passport-holders require a visa, which can be purchased on arrival (US$80) or in advance from the Mozambique High Commission in London for £40 (mozambiquehighcommission.org.uk).
Double rooms at Ibo Island Lodge (00 258 269 60549; iboisland.com) start at US$670 (£447) full board, including a guided tour of the old town.
Steppes Travel (01285 880 980; steppestravel.co.uk) can arrange specialist tours of Mozambique. A seven-night package, including three nights at Ibo Island Lodge and four nights on safari at Gorongosa National Park, costs from £3,750 per person, including all international and regional flights, transfers, game drives. and accommodation.