They moved as a group down the passageway and waited behind Kurt as he peered up and down the street. At last he turned and nodded, as if to indicate all was clear. He buttoned up his greatcoat, checked his cap was at the correct angle and put his semi-automatic pistol into his side pocket. Then, without saying a word, he stepped confidently into the street.

Bruno followed a few seconds later; he looked terrified, the sweat pouring from his forehead and his hands trembling violently as he put his hat on.

‘We’ll be at the factory as planned tomorrow morning,’ Otto whispered. ‘We’ll see you then.’ Bruno looked at him as if he was mad: tomorrow morning was a country so far away he had no expectation of ever getting anywhere near it.

Otto made to move out of the passageway almost immediately after Bruno had left it, but Prince put his hand on the other man’s arm to stop him. ‘Give it a minute.’

He was back in Matlock now, being trained for what they called ‘out and about’, which made it sound like a nature ramble rather than the deadly serious matter of how to operate in a town: how to avoid being followed and what to do if you were stopped.

Don’t walk too fast.

Don’t walk too slowly.

Don’t keep looking behind you: avoid doing so where possible.

At a junction is the best time to look around you.

Resist the temptation to stop and look in shop windows, especially at night. It can appear too obvious.

If you’re stopped, make sure you can explain where you’ve come from and where you’re going.

If you’re with someone else, they will most likely split you up before questioning you, so make sure you have the same story.

Keep your hands out of your pockets, otherwise they may think you’re armed.

Don’t argue when you’re stopped, but do appear slightly annoyed: if people are too compliant, that can look suspicious too.

He had felt much of it was obvious, but they’d made him memorise it: they called these the Nine Steps, and a couple of times he’d been woken up in the middle of the night and forced to recite them. Now he was going through them in his mind.

By the time they left the passageway, there was no sign of either Kurt to their left or Bruno to their right.

‘Walk a bit slower, Otto.’

‘You sound as if you’ve done this before.’