Escorting the convoy home

From the bridge of the destroyer the convoy looked like a slow-moving town spread across the sea — column after column of merchant ships, low and patient, rolling northward through the swell with the escorts fussing around their edges like sheepdogs around a flock.

The signalman's war was fought with a lamp and a pair of aching eyes. Hour after hour he read the winking messages passing between the ships and sent his own in reply, and in between he searched the grey water for the one thing he hoped never to see: the thin line of a periscope, or the sudden white scar of a torpedo track.

"You were tired in a way that's hard to describe," he wrote. "Not from working hard, but from watching. Days of it. Your eyes would start to invent things — a shadow, a splash — and you learned not to trust them, and then one day the thing they invented turned out to be real."

When a ship was hit the escorts turned inward at once, dropping patterns of depth charges that shook the whole sea, while the convoy plodded on regardless. The hard rule was that the merchant ships must not stop; to stop was to become the next target. The rescue of survivors was left to the small ships detailed for it, and to luck.

The convoy that reached harbour a few days later was two ships fewer than the one that had set out. On the quayside no one made a fuss. The men went ashore, slept, and in a day or two turned around to do it all again — the long, grey, unglamorous work that, ship by ship, kept the country fed and fighting.