‘That’s right,’ said Simon before anyone else could answer. ‘We know you were just about on the spot when he yelled. We know you took pretty good care to keep us off the path while you went back there yourself. We know you wouldn’t have had to say anything if Bell hadn’t come along and found you. You’re the only one of the lot of us except Uncle James that’s seen this gap in the path. You seem to have got hold of the idea that everything you say goes for gospel. Well, by cripey, it doesn’t for mine. By my idea you’ve had a free run of the hot air round here for a bit too long. There’s one other thing we know about you. What about that stuff with your pipe?’

‘Simon!’ said his father and uncle together.

‘What about it? Come on. What about it?’

‘Simon, will you…’

‘No, no, please!’ begged Falls. ‘Do let us hear about this. I’m completely baffled, I assure you. Did you say my pipe?’

‘I’m not saying another thing, Uncle. Keep your shirt on.’

Colonel Claire looked coldly at his son and said: ‘You’ll come and speak to me afterwards, Simon. In the meantime you will be good enough to say nothing. I am ashamed of you.’

‘Damned young cub,’ Dr Ackrington began, and his sister at once said: ‘No, James, please. It’s for his father to speak to him, dear, if he’s done wrong.’

‘I’m sorry,’ Simon muttered ungraciously. ‘I didn’t mean to…’

‘That will do,’ said his father.

‘Well,’ said Falls, ‘since this seems to be another little mystery that is to remain unsolved, perhaps, Ackrington, you would sum up for us.’

‘Certainly. I’m afraid,’ said Dr Ackrington, clearing his throat, ‘that beyond establishing a species of alibi in three cases, and also clarifying the situation generally, we do not appear at first glance to have attained very much.’

‘Hear, hear,’ said Gaunt.

‘Nevertheless,’ continued Dr Ackrington, quelling him with an acid stare, ‘there are certain valuable points to be noted. The gap in the path was not there before the concert. I didn’t see it on my return and as Claire was close behind me it seems most unlikely, indeed impossible, that it could have appeared before he got there or that even he could have missed it. We are agreed that the clod of mud could only have been dislodged by considerable force and we know that it bears the deep impression of a nailed boot. The only two members of our party wearing nailed shoes or boots appear to have alibis. Questing must have entered the thermal reserve after Claire and I had crossed it and after his scene with Gaunt. What was he doing in the interim?’

‘Having one with the boys?’ Simon suggested.