Hutchman glanced at Andrea, who eyed him bleakly, and he realized he was getting nowhere by standing on his dignity. “That’s correct. Look, I tried to play a very childish practical joke and now I realize just how stupid it was. Can’t we — “

“I’m a mathematician myself,” Welland interrupted. “Not in your league, of course, but I think I have some appreciation of genuine creative maths.”

“If you had, you’d recognize an outright spoof when you saw one.” An idea formed in the back of Hutchman’s mind. “Didn’t you notice the anomaly in the way I handled the Legendre functions?” He smiled condescendingly, and waited.

“No.” Welland lost a little of his composure. He reached into his inside pocket, then changed his mind, and withdrew his hand — but not before Hutchman had glimpsed and identified the corner of a white envelope. “I’m going to take some convincing about that.”

Hutchman shrugged. “Let me convince you, then. Where are the papers?”

“I’ll keep the papers,” Welland snapped.

“All right.” Hutchman smiled again. “If you want to make a fool of yourself with your Party bosses, go ahead. To me it’s all part of the joke.” He half-turned away, then sprang at Welland, throwing the other man’s jacket open with his left hand and grasping the envelope with his right. Welland gasped and clamped his hands over Hutchman’s wrists. Hutchman exerted all the power of his bowtoughened muscles, Welland’s grip weakened, and the envelope fluttered to the floor. Welland snarled and tried to drag him away from it and they went on a grotesque waltz across the room. The edge of a long coffee table hit the back of Hutchman’s legs and to prevent himself going down he stepped up onto it, bringing Welland with him. Welland raised his knee and Hutchman, trying to protect his groin, flung the other man sideways. Too late, he realized, they were close to the window. There was an explosive bursting of glass, and suddenly the cool November air was streaming into the room. The lacy material clogged around Hutchman’s fingers and mouth as he looked downwards through angular petals of glass. People were running into the forecourt, and a woman was screaming. Hutchman saw why.

Welland had landed on a cast-iron railing and, even from a height of four storeys, it was obvious that he was dead.

Detective Inspector Crombie-Carson was a lean, acidulous man who made no concessions to his own or anybody else’s humanity. His face was small but crowded with large features, as though all the intervening areas had shrunk and caused the dominant objects to draw together. Horn-rimmed spectacles, a sandy moustache, and one protuberant mole also found room, somehow, on his countenance.

“It’s damned unsatisfactory,” he said in clipped military tones, staring with open belligerence at Hutchman. “You left your home on a Sunday morning and drove from Crymchurch to here to have a drink with Miss Knight?”

“That’s it.” Hutchman had been feeling ill since he saw the television-camera team among the crowd below. “Andrea and I have known each other since our university days.”

“And your wife has no objections to these little excursions?”

“Ah… my wife didn’t know where I was.” Hutchman drew his lips into the semblance of a smile and tried not to think about Vicky. “I told her I was going to work for an hour.”

“I see.” Crombie-Carson gazed at Hutchman in disgust. From the start of the interview he had shown no trace of the behind-this-badge-I’m-just-another-human-being attitude with which many police officers eased their relationship with the public. He was doing a job for which he expected to be hated and was more than ready to hate in return. “How did you feel when you arrived and found that Mr. Welland was already here with Miss Knight?”

“I didn’t mind — I knew he was here before I set out. I told you I merely stopped by for a drink and a chat.”

“But you told your wife you were going to work.”

“My domestic situation is complicated. My wife is… unreasonably jealous.”

“How unfortunate for you.” Crombie-Carson’s mouth thinned for an instant, packing his features even closer together. “It’s surprising how many men I encounter who have the same cross to bear.”

Hutchman frowned. “What are you trying to say, Inspector?”

“I never try to say things. I have an excellent command of the language, and my words always convey my exact meaning.”

“You seemed to be implying something more.”

“Really?” Crombie-Carson sounded genuinely puzzled. “You must have read something into my words, Mr. Hutchman. Have you been to this flat on previous occasions?”

“No.” Hutchman made the denial instinctively.

“That’s strange. Both the occupants of the ground-floor flat say that your car was…”

“During the day, I meant. I was here last night.”

The Inspector permitted himself a little smile. “Until about 11:30?”

“Until about 11:30,” Hutchman agreed.

“And what excuse did you give your wife last night?”

“That I was out drinking.”

“I see.” Crombie-Carson glanced at the uniformed sergeant who was standing beside Andrea, and the sergeant nodded slowly, conveying a message which Hutchman could not understand. “Now, Miss Knight. As I understand it, Mr. Welland decided to visit you this morning.”

“Yes.” Andrea spoke tiredly, exhaling grey smoke as she stared at the floor.

“Sunday appears to be a busy day for you.”

“On the contrary.” Andrea gave no indication of having seen any semantic shadings in Crombie-Carson’s remark. “I make a point of relaxing on Sundays.”

“Very good. So after Mr. Welland had been here for about an hour you decided it would be a good idea for him to meet Mr. Hutchman.”

“That’s right.”

“Why?”

Andrea raised her eyes. “Why what?”

“Why did you think a Communist high-school teacher and a guided-missile expert should get together?”

“Their professions or politics didn’t come into it. I often introduce my friends to each other.”

“Do you?”

“Of course.” Andrea was pale, but in control of herself. “Besides, people with dissimilar backgrounds often react together in a more interesting way than…”

“I can well believe it.” Crombie-Carson thrust his hands into the pockets of his gray showerproof, walked to the shattered window, and looked down into the street for a moment. “And this morning, while your two visitors were reacting interestingly with each other, Mr. Welland decided to get up on this coffee table and fix your curtains for you?”

“Yes.”

“What was wrong with the curtains?”

“They weren’t closing properly. The runners were jamming on the rail.”

“I see.” Crombie-Carson twitched the curtains experimentally. They slid easily along the rail with a series of subdued multiple clicks.

Andrea eyed him squarely. “Aubrey must have cleared the obstruction before he fell.”

“Probably.” The Inspector nodded morosely. “If he had still been working on the rail he might have clutched it when he felt the table tip up underneath him. That way he would have pulled panels and everything down — but he mightn’t have gone out.”

“I think he had finished,” Hutchman put in. “I think he was in the act of getting down when the table couped.”

“Couped! An interesting verb, that. Scots, isn’t it?”

“I don’t know,” Hutchman said warily.

“You were both in the room when the accident happened?”

“Yes, but we weren’t looking at the window. There was a crash… and he was gone.”

Crombie-Carson gave Andrea a speculative look. “I understand that as well as teaching mathematics Mr. Welland was games master at his school.”

“I believe he was.”

“What an unfortunate time for his reactions to fail him — perhaps he had had too much to drink.”

“No. He hadn’t drunk anything.”