She smiled, but did not reply.

‘You were following me?’ he said.

‘Why were you so anxious about Mr Vincent?’

Hepton shrugged. ‘It’s no secret. Paul was taken ill. He’s a friend of mine, as you yourself said. So, naturally, I was worried.’

‘But there’s more to it than that, isn’t there?’ Her voice had taken on a hard, professional edge. He stood up.

‘Look,’ he said, ‘I’m sorry, but I’ve got no proof that you are who you say you are – not that you’ve said very much.’ He walked to the window and stared down into the street. An old man was stooping to pick up a discarded piece of fruit from the side of the road.

‘Very good, Martin. I was beginning to wonder if you’d ever get round to asking. I thought you’d forgotten procedures. Take this.’ She produced a slip of paper from her skirt pocket and rose from her chair to hand it to him.

From close up, he could smell the subtle soap she used. She wasn’t wearing perfume, though; either that or his nose wasn’t attuned to it. He stared at the numbers on the paper.

‘It’s a telephone number,’ she said. ‘Ex-directory; you won’t have come across it before. If you dial it, you will find yourself speaking to your superior, Mr Fagin. It’s a direct line. He’ll give you clearance to speak to me, and he’ll promise also to give that permission in writing. Don’t worry, nothing you might say to me will get back to him.’

‘You don’t have any identification on you?’

‘Nothing formal,’ said Harry. ‘It’s against the rules. I can let you have a library ticket or my credit card, but that’s about it.’

Hepton smiled but was already picking up the telephone. The receiver at the other end was answered after the very first ring.

‘I suppose that’s you, Martin. I was told to expect a call. Listen, I want you to tell them everything, do you understand? It may be more important than you think. Don’t let it spoil your holiday, though; just get it all off your chest and then you can enjoy yourself.’

As Hepton listened to Fagin’s unmistakable voice, saying little himself, he watched Harry picking invisible hairs off the arms of her chair. His head was spinning. What is all this about? A little while ago, Fagin hadn’t seemed interested in anything he or Paul Vincent might have to say. Yet now he was ordering Martin to tell all. He wrenched his thoughts back to the here and now in time to catch Fagin’s final statement:

‘If you keep anything from them, you could get into serious trouble, and they’ll know if you’re hiding something. That’s their job. I must go now. Goodbye.’