By day, but above all by night, the city is a bombardment of the senses. There are streetlights, but they are dead. The congested highway into town is illuminated by the myriad flickers of lanterns, candles and tiny fires of roadside hawkers. The air is heavy, humid, scented by smoke, spice and excrement. The place pullulates with anarchy and vague menace. This, surely, is what civilisation looks like in the instant before its disintegration.
I search for parallels. Russia, that other nearly failed state, a melange of shoddiness and corruption, where no one trusts anyone else, comes closest. But it lacks the teeming vitality of Nigeria, the place's inventive improvisation, even in its scams. Next day, we drive from Lagos to the farm of Olusegun Obasanjo, the president-elect, at Ota. This, too, is a journey of the soul - 15, maybe 20 miles along a road that is a slowly eddying river of cars, yellow taxi-buses, animals and people. It is lined by advertising hoardings that could have come from 1950s Britain, featuring anything from gripewater and Guinness to God.
Beyond stretch vendors, kiosks, shops, and small factories, a panorama of every economic activity known to man. Some of the side roads are open sewers. There are great fields of trash, levelled and picked over by the poorest of the poor. Obasanjo, they say, rarely ventures into Lagos - one can see why. Democracy has brought a buzz of hope. But the drive to Ota has you wondering how anyone could even think of reforming the place. In that sense too, Nigeria resembles Russia. Its problems seem so vast; just where do you even start?
That evening, an hour's flight west, I find another former British colony - and another Africa. This is Africa for beginners. There are computers at hotel check-in desks. You can use a credit card without fear of financing the local mafia for a fortnight. Accra is neat, tidy and utterly unthreatening. Not only are there traffic lights and street lights: they work.
And Ghana has Flight Lieutenant Jerry Rawlings - surely the only African president to take power in a coup, hand it back to the politicians a few months later, then seize it back again in disgust at all the corruption. Eighteen years later he's still there. He holds court in his residence at Osu Castle, the fortress the Danes built in the 1670s to secure their slice of the trading and slaving action on the Gold Coast.
The castle is blinding white, the lawn outside brilliant green, studded with flame trees, hibiscus and frangipani. By now Robin Cook has been joined by his French counterpart, Hubert Vedrine, but the double dose of VIPs doesn't stop Rawlings from turning up 30 minutes late. It's worth the wait, though.
He has the magnetic presence and the easy charm of Bill Clinton, but twice the dignity and natural sense of command. As the press is ushered out, he starts to lecture his guests about the evils of big foreign corporations, perverting local democracy with their bribes and kickbacks. Maybe Ghana is a little like Nigeria after all.
Another hour's flight and it's the Cote d'Ivoire, the proclaimed showcase of French Africa. The notorious Gallic omnipresence is less visible than I expected. The road direction signs are the classic French blue/black on cream, but Abidjan seems infinitely more Africa than France.
This is the high point of the trip, where France and Britain are to make their African peace after 150 years of feuding. The French embassy exudes entente cordiale, with President Chirac's portrait to the right of the entrance to the conference hall, and the Queen's to the left. But has anything really changed? Cover your mind's eye with a sepia veil, and the facing rows of middle-aged, white and mostly male ambassadors of the two countries could be plotting a carve-up of the continent, not ending one. For one British envoy in attendance, fortified by a decent French lunch, it's deja vu all over again: "Place smells of High Commission. Bloody viceroy's palace, if you ask me."
But the meeting seems to get off to a easy, post-prandial start. At his parting press conference, our Foreign Secretary sums up the occasion as "Farewell to Fashoda", an allusion to what the French believe to this day was a dastardly piece of British treachery in 1898, at the height of the Scramble for Africa, which cost them control of the upper White Nile.
As he sits there in a West African airport, Mr Cook looks like a slightly self-important but well-meaning District Commissioner presenting his annual report to the governor; an orderly man in charge of a small orderly world. But then I think back to Lagos, to the road to Ota, and all I see is disorder. And I wonder, with the enchanted despair of every newcomer to Africa, whether anything can save Africa from itself.