He walked on, rubbing earth from his palm. The road widened into the belvedere. There was a telescope and, set into the low wall, a slab of Portland stone. “At this spot Her Majesty Queen Elizabeth II and HRH the Duke of Edinburgh stood and looked over Gibraltar. 10 May 1954.” Across the slab had been sprayed FUCK IS GOOD.

Wavery stood and looked. Below and to the right of him was the reclamation project where deposits from the Straits Tunnel had soaked up the sea. An empty lorry moved towards Europa point, disappearing into the rock mouth. From that mouth the tunnel began its fourteen-mile journey to the African coastline.

Wavery placed his plastic bag on the wall and he searched for the city across the Straits. It was to be home for a year. Not for a moment had he dreamed he would be taking up this appointment without his wife. Nor had it crossed his mind that it would be located on the southern coast of the Mediterranean. He was anxious to have one glimpse of his last post.

“You’ll remember the Yeats poem,” Cullis had said, when informing Wavery of the appointment. The Permanent Under Secretary quoted in a Scottish accent, “The heron-billed pale cattle-birds that . . . cross the narrow straits”. He couldn’t remember the title.

While not knowing the poem, Wavery was, nevertheless, familiar with the stretch of water below. He wanted to suppress his knowledge, but a dozen classical and historical allusions bobbed into his head. The channel had been dug by Hercules for his Tenth Labour. After separating the continents, the god had erected two pillars, one on either side. Where Wavery stood had been the edge of the world, beyond which orbis terrarum crumbled into the Green Sea of Darkness. These Straits were the key to the association of the Old World and the New. The Phoenicians had sailed through them, as had St Ursula, and Columbus, too, who had nearly drowned when his boat was attacked by pirates. He had reached land clinging to a plank. Wavery thought, I used to make love with Penny on that shore, outside a pleasant town called Lagoa. But he couldn’t help seeing a man in the water, clinging to the small spar the Foreign Office had tossed to him.

Wavery fumbled with a coin. Like Columbus, he had travelled the world. He had lived in seven of its countries. Now he was destined, in his final days, to be chained to a rock. From that rock, the southern pillar of Hercules, the Moors had invaded Europe, Count Julian sending Tarik’s men to avenge his daughter’s rape by the King of Spain. Wavery fed the coin into the telescope and swivelled the lens towards where he calculated Abyla must be. The lens would open for two minutes. He pressed his right eye to the glass. He had looked back long enough, he told himself. Now, in late middle age, he must look to the future.