‘We had better be going,’ he said.

‘But a man’s dead,’ Hepton protested.

‘Good reason for us not to be here, my friend.’

‘Who are you?’ Hepton asked.

‘Come on.’ The man gripped his arm. ‘We’ll take a ride.’ He propelled Hepton towards a waiting black cab. Hepton hesitated, but climbed into the back of the taxi, followed by the man, who told the driver to head towards Holborn. Then he turned to Hepton. ‘I’m sorry for Mr Devereux,’ he said. ‘But there’s nothing more to be done. My name is Vitalis, and yours is …?’

‘Martin Hepton.’

Vitalis nodded, giving no indication that he recognised the name. ‘Were you a friend of Mr Devereux?’

‘In a way. And you?’

‘Yes. I suppose you could call me a friend.’

‘A friend who carries a gun.’

Vitalis smiled, but said nothing.

‘A friend who carries a gun because he fears danger,’ Hepton continued. ‘Because he knows Devereux’s life is threatened.’

Vitalis shrugged.

‘Who are you?’ Hepton persisted.

Vitalis didn’t respond. ‘The time for questions is past,’ he said. ‘Now is a time for action.’

Hepton found himself agreeing with this.

‘The assassin,’ Vitalis said, ‘you said it was a she.’

‘A woman,’ Hepton said. Vitalis nodded. ‘You were his …’ Hepton sought the correct word and found it. ‘His controller. You were Devereux’s controller, weren’t you?’

‘What makes you say that?’ Vitalis’ tone was amused.

Hepton nodded to himself. ‘Cam told me,’ he said, ‘about some mysterious man at the Argos base. But the only way he could have known about such a person was if he had gone investigating, opening closed doors, that sort of thing. Because the mystery man would have been in a room of his own, with his own computer and everything. But why would Cam be spying? The answer’s simple, isn’t it?’ He fixed Vitalis with his gaze. ‘He was a spy, he was spying for you.’

‘Bravo, Mr Hepton,’ said Vitalis. ‘Yes, well done.’

‘And he had come to London to defect?’ It was an educated guess.

‘He thought his useful time was over. It happens.’

Another question was on Hepton’s lips, but he swallowed it back. If Devereux were about to defect, why would the Russians keep him on so long a leash, and leave him unprotected to boot? His useful time was over. His useful time was over, and so he was expendable … Hepton stared at the driver’s back. Was he too a spy? When would the killing stop?

‘Where are we going?’ he asked.

‘Don’t be alarmed. We’re dropping me off near my place of work, and then the driver will take you back to your hotel.’ Vitalis’ eyes twinkled. ‘I presume you are staying in a hotel?’

Hepton made no answer. Vitalis just nodded and smiled. He seemed amused by everything.