“But you’ll forgive me for asking. I don’t want to seem rude, but it’s not every day that an old Merton chum comes swanning into your POW camp wearing an SS uniform!”

Good old Test Tube. He was just the same, thought Lockhart, complete with his scratchy hair (although a little balder), and his thick-rimmed glasses (with an arm missing, but maybe they were like that at Oxford). He still spoke rapidly, half an octave higher than most people, and overemphasized certain words.

“Cigarette?” Lockhart asked.

“No, but I’ll take some all the same. Barter.”

“Please—take them all.”

Barham left the packet on the table.

“So come on,” he said. “Why are you here? What are you doing? Come on, come on.”

Lockhart told him the truth—all of it. He owed it to him. After he had finished, Ted took a cigarette, which Lockhart lit. They sat in silence, Lockhart feeling uneasy, hoping that Test Tube had believed him.

“I…I…don’t know what to say,” Barham stuttered. “It just seems too fantastic. All of it.”

“But Ted, it’s true,” Lockhart insisted. “And I need your help. You must know how to deal with this gas.”

“I’m not sure if I do.”

Lockhart’s shoulders slumped.

“Please, Ted, you must trust me. Can’t you see how important this is? If the Germans use this gas, then thousands, maybe millions, might die. It could alter the whole war. Can’t you see that?”

Ted shook his head.

“It’s just not possible, nothing can be that toxic.”

“So you think the whole thing’s bunkum?”

Barham pushed his glasses back up the bridge of his nose and looked at Lockhart.

“Well, I’ve certainly never heard of such a gas. Why can’t you tell me more? What’s it made from?”

Lockhart shook his head.

“Sorry, I was hoping you might know, or might be able to guess. Couldn’t you at least tell me how they deal with other poison gases? There must be some way of getting rid of them.”

Barham looked at the floor and scratched his head with the hand holding the cigarette. Lockhart noticed that some ash fell into his hair.

“The only way I can think of…” said Barham.

“Yes?”

“…is to find some other chemical that will neutralize it.”

“How the hell am I going to find that?”

Lockhart regretted showing his exasperation.

“Perhaps if you got hold of the formula, I might be able to help you.”

Lockhart shook his head.

“No, sorry, Ted, there’s no time for that. If the Germans are going to use it, they’re going to use it soon. Please, think.”

This was followed by a lot more head-scratching.

“Well…actually…no,” said Barham. “No, it’s ridiculous.”

“What? Tell me.”

“I suppose you could try blowing it up.”

“But surely that would release the gas?”

“Not if you blew it up in a chamber. You’d need something pretty heavy-duty, but it would probably work….”

Ted was speaking quickly now.