Teresa presented the sergeant with a bill, and he took a long time to check the numbers then count out the money.

At last they were able to take their leave, with empty backpacks and lighter hearts.

They walked back down the mountain half a mile, then they split up. Teresa went on down with the Frenchmen and the horses. Lloyd and the fugitives turned on to an upward path.

The German sentries at the clearing would probably be too drunk by now to notice that fewer people were coming down than went up. But if they asked questions, Teresa would say some of the party had started a card game with the soldiers, and would be following later. Then there would be a change of shift and the Germans would lose track.

Lloyd made his group walk for two hours, then he allowed them a ten-minute break. They had all been given bottles of water and packets of dried figs for energy. They were discouraged from bringing anything else: Lloyd knew from experience that treasured books, silverware, ornaments and gramophone records would become too heavy and be thrown into a snow-filled ravine long before the footsore travellers crested the pass.

This was the hard part. From now on it would only get darker and colder and rockier.

Just before the snowline, he instructed them to refill their water bottles at a clear cold stream.

When night fell they kept going. It was dangerous to let people sleep: they might freeze to death. They were tired, and they slipped and stumbled on the icy rocks. Inevitably their pace slowed. Lloyd could not let the line spread: stragglers might lose their way, and there were precipitous ravines for the careless to fall into. But he had never lost anyone, yet.

Many of the fugitives were officers, and this was the point where they would sometimes challenge Lloyd, arguing when he ordered them to keep going. Lloyd had been promoted to major to give him more authority.

In the middle of the night, when their morale was at rock bottom, Lloyd announced: ‘You are now in neutral Spain!’ and they raised a ragged cheer. In truth he did not know exactly where the border was, and always made the announcement when they seemed most in need of a boost.

Their spirits lifted again when dawn broke. They still had some way to go, but the route now led downhill, and their cold limbs gradually thawed.

At sunrise they skirted a small town with a dust-coloured church at the top of a hill. Just beyond, they reached a large barn beside the road. Inside was a green Ford flatbed truck with a grimy canvas cover. The lorry was large enough to carry the whole party. At the wheel was Captain Silva, a middle-aged Englishman of Spanish descent who worked with Lloyd.

Also there, to Lloyd’s surprise, was Major Lowther, who had been in charge of the intelligence course at Tŷ Gwyn, and had been snootily disapproving – or perhaps just envious – of Lloyd’s friendship with Daisy.