“I’m most grateful, my lord,” said Carman, “for your confirmation of Mr. Collier’s undoubted qualifications as an expert witness.” The judge frowned, but made no further comment. “Mr. Collier, can I confirm that you were the senior customs officer on duty on the morning the defendant, Mr. Bishara, was arrested and taken into custody.”

“Yes I was, sir.”

“When Mr. Bishara entered the green channel, indicating that he had nothing to declare, did you stop him and ask to inspect his baggage?”

“Yes I did, sir.”

“How much luggage was he carrying?”

“Just an overnight bag, nothing else.”

“And was this simply a random check?”

“No, sir. We had received a tip-off that a passenger on flight 207 from Lagos would be attempting to smuggle a consignment of heroin into the country.”

“How was this tip-off made?”

“By phone, sir. About thirty minutes before the plane landed.”

“Did the informant give you his name?”

“No, sir, but that’s not unusual because informants in cases of this kind are often drug dealers themselves. They may want a rival removed or punished for not having paid for a previous consignment.”

“Was the conversation with the informant recorded?”

“All such conversations are taped, Mr. Carman, in case they are needed as evidence in a trial at a later date.”

“Might I suggest, my lord,” said Carman, looking up at the bench, “that this would be an appropriate moment for the jury to hear the tape?”

The judge nodded, and the clerk of the court walked over to a table in the center of the room where a Grundig tape recorder had been set up. He looked toward the judge, who nodded once again, and pressed the Play button.

“Customs office, Heathrow,” said a female voice.

“Put me through to the senior customs officer.”

“May I ask who’s calling?”

“No, you may not.”

“I’ll see if he’s available.” The hum of the whirring tape continued for some time before another voice came on the line. “SCO Collier. How can I help you?”

“If you’re interested, I can tell you about some drugs that a passenger will be trying to smuggle in today.”

Sebastian noticed that Mr. Gray was making copious notes on his yellow pad.

“Yes, I’m interested,” said Collier. “But first, would you tell me your name?”

“The passenger’s name is Hakim Bishara. He’s well known in the trade and is traveling on flight 207 from Lagos. He has thirteen ounces of heroin in his overnight bag.” Click, burr.

“What did you do next, Mr. Collier?”

“I contacted a colleague in passport control and asked him to inform me the moment Mr. Bishara had been cleared.”

“And he did so?”

“Yes. When Mr. Bishara entered the green channel a few minutes later, I stopped him and inspected his overnight bag, the one piece of luggage in his possession.”

“And did you find anything unusual?”