He lit another cigarette. When he looked up he was no longer smiling.

In the wheelhouse of the Kontoro Janvier, the first officer, yawned as he bent over the chart. He made a quick calculation and threw down his pencil. By dead reckoning they were forty miles west of Ushant and the weather forecast wasn’t good. Winds of gale force reported imminent in sea areas Rockall, Shannon, Sole and Finisterre.

For the moment there was only an unnatural calm, the sea lifting in a great oily swell. Janvier was tired, his eyes gritty from lack of sleep. A native of Provence, he had never managed to get used to the cold of these northern seas and he shivered with distaste as he gazed out into the grey dawn.

Behind him the door to the companionway clicked open and the steward entered holding a steaming cup of coffee in each hand. He gave one to Janvier and the other to the helmsman, taking his place at the wheel for a few moments while the man drank.

Janvier opened the door and walked out on to the bridge. He stood at the rail drinking his coffee and breathing deeply of the cold morning air, feeling considerably more cheerful. Once across Biscay there was the long run south to look forward to Maderia, then the Cape and sun all the way.

He finished his coffee, emptied the dregs over the side and started to turn.

A hundred yards to starboard there was a sudden surge in the oily water. It boiled in a white froth and a submarine broke through to the surface, strange and alien like some primeval creature in the dawn of time.

Janvier stood at the rail, trapped by surprise. As he watched, the conning-tower hatch opened and a young officer in peaked cap appeared, followed by a sailor who immediately hoisted a small ensign. A sudden gust of wind lifted it stiffly, the red, white and blue of the tricolour standing out vividly against the grey clouds.