‘None of your damned business. Now, Maxie, don’t lose your temper. That pectoral is my ace in the hole. You don’t suppose I’ll meekly hand it over without getting something in return, do you?’

‘Need I ask what?’

‘Surely not. And please don’t insult my intelligence by suggesting you’ll turn her loose after I deliver the goods. I want her out of here and safely back at the Embassy. As soon as she telephones to say she’s there, and the ambassador confirms it, I’ll get the pectoral for you.’

‘We could force you to tell us,’ Max said.

‘You could certainly try,’ John said agreeably. Leaning against a chest of drawers, hands in his pockets, he was putting on a pretty good imitation of languid self-confidence, but the tension that vibrated along every nerve was evident to me at least. He was trying very hard not to look at me.

‘But it’s not the most efficient method of attaining your ends,’ he went on. ‘You know me well, Maxie; do you suppose I give a damn about the museum or the tomb or any bloody antiquity on the face of the earth? I’ll even go through with the robbery, if that’s what you want.’

‘You will?’ Blenkiron said eagerly. ‘But you said – ’

John raised an eyebrow. ‘I didn’t object to robbing the museum. The thing that put me off a bit was a strong suspicion that I wouldn’t survive the attempt. I’m willing to take my chances with the ordinary security system, but I object to being shot or stabbed in the back by one of my purported assistants.’

Max looked a little embarrassed. ‘I was against that,’ he said. ‘I felt sure you would expect something of the sort and there really was no need – ’

John cut him off. He was looking at Max, but I knew he was aware of every move Mary made and every breath she took. She was the most unstable and unpredictable factor in the structure of mutual self-interest he was building with such agonizing deliberation. I was afraid to move or speak for fear of shaking it. And I knew why he wouldn’t look at me.