“The place we are going to is called Mittelbau,” said Lockhart. “It is a factory built into the Kohnstein Mountain near Nordhausen, about a hundred kilometers from here. On Sunday morning, we will drive there in the truck, dressed in our uniforms, although we shall have to strip them of the BFC insignia—Simpkin, I’d like you to see to that. Upon arrival, we shall present ourselves to the commandant. We will say that we have been sent from Berlin, and tell them that we are delivering some machinery, as well as forming a new guard detachment.”

“What if this doesn’t work?” Hull chipped in.

“It will,” said Lockhart, producing a piece of paper from his tunic pocket, “because I have typed orders from Berlin to that effect. I expect I will be told that they are not expecting us. I will answer that that’s not my fault—they can either take it or leave it and incur the wrath of the supposed signatory—a certain Brigadeführer Karl Kammler. I’m gambling that they’ll take it. The last thing anyone is expecting is a raid carried out by an SS unit.”

“And what happens when we’re actually in the plant?” asked Pugh.

“Simple,” said Lockhart, pointing to the blackboard. “We make our way to hall number 44 here, which is where I suspect the gas is held. It may be at this stage that we’ll have to engage the enemy, but I’m hoping that the bluff will hold. We’ll then park the truck as close to the chemical store as possible, and deal with the gas.”

“But how?” Maclaren asked.

“I’ll tell you that in a moment,” said Lockhart.

“There seems so much that can go wrong,” said Catchpole. “We could be stopped at any moment. Someone could smell a rat….”

“I know, I know,” said Lockhart. “But if you’ve got a better idea, then let’s hear it. Remember, simple plans have less to go wrong with them. Don’t forget, Mittelbau is a vast place—they have such comings and goings every day. We’ll be just another set of faces, just another unit of bored men looking forward to a Sunday afternoon off. And because it’s the weekend, those on duty will probably be feeling a little more slack.”

“It sounds mad!” said Prain.

“Perhaps,” said Lockhart, “but it would be a greater madness not to try. Just imagine the whole of London choking to death on an invisible cloud of gas. It would be the worst terror on earth, destruction and murder on a scale never seen before. We can’t just sit by and let it happen. Many of you have families in London—are you willing just to let them die? And where will they hit next? Manchester? Liverpool? The whole British population could be eradicated. Just think of it for a minute.”