Dr Ackrington beat his fist on the table and began to stutter. Dikon thought they were in for a tirade, but with a really terrifying effort at self-control Dr Ackrington pulled himself up, gripped the edge of the table and at last addressed Questing coherently and with a kind of calmness. He outlined the story of Smith’s escape, adding several details that he had evidently gleaned after leaving the dining-room. At first Questing listened with the air of a connoisseur, but as Dr Ackrington went on he began to get restless. He attempted several interjections but was ruthlessly talked down. Finally, however, when his inquisitor enlarged upon his abominable behaviour in deserting a man who might have been fatally injured, Questing raised a cry of protest. ‘Fatally injured, my foot! He came charging up the bank like a horse, don’t you worry. It was me that looked like getting a fatal injury.’

‘So you turned tail and bolted?’

‘Don’t be ridiculous. I didn’t want a lot of unpleasantness, that’s all. I wasn’t deserting the chap. There was another chap there to look after him. He came bowling down the hill after it had happened. A chap in a blue shirt. And the train stopped. I didn’t want a lot of humbug with the engine driver. Smith was all right. I could see he wasn’t hurt.’

‘Mr Questing, did you or did you not look at the signal before you beckoned Smith to cross the bridge?’

For the first time, Questing looked acutely uncomfortable. He turned very red in the face and said: ‘Look, Doctor, we’ve got a very, very distinguished guest. We don’t need to trouble Mr Gaunt—’

‘Not at all,’ said Gaunt. ‘I’m enormously interested.’

‘Will you answer me?’ Dr Ackrington shouted. ‘Knowing that the evening train was due, and seeing the fellow hesitated to cross the railway bridge, did you or did you not look at the signal before waving him on?’

‘Of course I looked at it.’ Questing examined the end of his cigar, glanced up from under his eyebrows and added in a curiously flat voice: ‘It wasn’t working.’

Dikon experienced that wave of personal shame with which an amateur reciter at close quarters can embarrass his audience. It was such a bad lie. It was so clearly false. Questing so obviously knew that he was not believed. Even Dr Ackrington seemed deflated and found nothing to say. After a moment Questing mumbled: ‘Well, I didn’t see it, anyway. They ought to have a wig-wag there.’

‘A red light some ten inches in diameter and you didn’t see it.’

‘I said it wasn’t working.’

‘We can check up on that,’ said Simon.

Questing turned on him. ‘You mind your own business,’ he said, but his voice missed the note of anger, and it seemed to Dikon that there was something he could not bring himself to say.