'Relax,' said Giles once they were outside. 'Don't forget we're the only two people who are sober.' He tucked the scarf around his neck so that it covered his chin, pulled down his cap, gripped the baton firmly and stooped slightly, as he was a couple of inches taller than the commandant.

As soon as the driver heard Giles approaching, he leapt out of the car and opened the back door for him. Giles had rehearsed a sentence he'd heard the colonel say to his driver many times, and as he fell into the back seat, he pulled his cap even further down and slurred, 'Take me home, Hans.'

Hans returned to the driver's seat, but when he heard a click that sounded like the boot closing, he looked back suspiciously, only to see the commandant tapping his baton on the window.

'What's holding you up, Hans?' Giles asked with a slight stutter.

Hans switched on the ignition, put the car into first gear and drove slowly towards the guard house. A sergeant emerged from the sentry box when he heard the vehicle approaching. He tried to open the barrier and salute at the same time. Giles raised his baton in acknowledgement, and nearly burst out laughing when he noticed that the top two buttons of the sentry's tunic were undone. Colonel Schabacker would never have let that pass without comment, even on New Year's Eve.

Major Forsdyke, the escape committee's intelligence officer, had told Giles that the commandant's house was approximately two miles from the compound, and the last two hundred yards were down a narrow, unlit lane. Giles remained slumped into the corner of the back seat, where he couldn't be seen in the rear-view mirror, but the moment the car swung into the lane, he sat bolt upright, tapped the driver on the shoulder with his baton and ordered him to stop.

'I can't wait,' he said, before jumping out of the car and pretending to undo his fly buttons.

Hans watched as the colonel disappeared into the bushes. He looked puzzled; after all, they were only a hundred metres from his front door. He stepped out of the car and waited by the back door. When he thought he heard his master coming back, he turned around just in time to see a clenched fist, an instant before it broke his nose. He slumped to the ground.

Giles ran to the back of the car and opened the boot. Terry leapt out, walked across to Hans's prostrate body and began to unbutton the driver's uniform, before pulling off his own clothes. Once Bates had finished putting on his new uniform, it became clear just how much shorter and fatter Hans was.

'It won't matter,' said Giles, reading his thoughts. 'When you're behind the wheel, no one will give you a second look.'

They dragged Hans to the back of the car and bundled him into the boot.

'I doubt if he'll wake up before we sit down for breakfast in Zurich,' said Terry as he tied a handkerchief around Hans's mouth.

The commandant's new driver took his place behind the wheel, and neither of them spoke again until they were back on the main road. Terry didn't need to stop and check any signposts, as he'd studied the route to the border every day for the past month.

'Stay on the right-hand side of the road,' said Giles, unnecessarily, 'and don't drive too fast. The last thing we need is to be pulled over.'

'I think we've made it,' Terry said as they passed a signpost for Schaffhausen.

'I won't believe we've made it until we're being shown to our table at the Imperial Hotel and a waiter hands me the breakfast menu.'

'I won't need a menu,' said Terry. 'Eggs, bacon, beans, sausage and tomato, and a pint of beer. That's my usual down at the meat market every morning. How about you?'

'A kipper, lightly poached, a slice of buttered toast, a spoonful of Oxford marmalade and a pot of Earl Grey tea.'

'It didn't take you long to go back from butler to toff.'

Giles smiled. He checked his watch. There were few cars on the road that New Year's morning, so they continued to make good progress. That was, until Terry spotted the convoy ahead of them.

'What do I do now?' he said.

'Overtake them. We can't afford to waste any time. They'll have no reason to be suspicious  -  you're driving a senior officer who wouldn't expect to be held up.'

Once Terry caught up with the rear vehicle, he eased out into the centre of the road and began to overtake a long line of armoured trucks and motorcycles. As Giles had predicted, no one took any interest in a passing Mercedes that was clearly going about official business. When Terry overtook the leading vehicle, he breathed a sigh of relief, but he didn't fully relax until he swept round a corner and could no longer see any headlights in his rear-view mirror.

Giles continued to check his watch every few minutes. The next signpost confirmed they were making good time, but Giles knew they had no control over when the commandant's last guest would leave and Colonel Schabacker would go in search of his car and driver.

It was another forty minutes before they reached the outskirts of Schaffhausen. They were both so nervous that hardly a word had passed between them. Giles was exhausted just sitting in the back seat, doing nothing, but he knew they couldn't afford to relax until they had crossed the Swiss border.

When they entered the town, the locals were just beginning to wake up; the occasional tram, the odd car, a few bicycles ferrying people who were expected to work on New Year's Day. Terry didn't need to look for signs to the border, as he could see the Swiss Alps dominating the skyline. Freedom felt as if it was touching distance away.

'Bloody hell!' said Terry as he slammed on the brakes.

'What's the problem?' said Giles, leaning forward.

'Look at that queue.'

Giles stuck his head out of the window to see a line of about forty vehicles, bumper to bumper, ahead of them, all waiting to cross the border. He checked to see if any of them were official cars. When he was sure there were none, he said, 'Drive straight to the front. That's what they'd expect us to do. If we don't, we'll only draw attention to ourselves.'

Terry drove slowly forward, only stopping when he reached the barrier.

'Get out and open the door for me, but don't say anything.'

Terry turned off the engine, got out and opened the back door. Giles marched up to the customs post.

A young officer leapt up from behind his desk and saluted when he saw the colonel enter the room. Giles handed over two sets of papers that the camp forger had assured him would pass muster at any border post in Germany. He was about to find out if he'd exaggerated. As the officer flicked through the documents, Giles tapped the side of his leg with his baton and glanced repeatedly at his watch.

'I have an important meeting in Zurich,' he snapped, 'and I'm running late.'

'I'm sorry, colonel. I'll get you on your way as soon as possible. It should only take me a few moments.'

The officer checked the photograph of Giles on his papers, and looked puzzled. Giles wondered if he'd have the nerve to ask him to remove his scarf, because if he did, he would immediately realize that he was too young to be a colonel.

Giles stared defiantly at the young man, who must have been weighing up the possible consequences of holding up a senior officer by asking him unnecessary questions. The scales came down in Giles's favour. The officer nodded his head, stamped the papers and said, 'I hope you won't be late for your meeting, sir.'