“Do you do much ringing yourself, Doctor?”

“Not as much as I would like to now, though I maintain my licence, of course. My eyesight is rather poor. My function is predominantly supervisory, you know. I see to the administration.”

“So you would not know anything about the mist-net guy which was used to strangle Mr. Todd?”

“No. Nothing at all. Nick Mardle is our keenest ringer. These boys are inclined to be untidy at times. Only the other day I noticed that he had six bird bags in his coat pocket. Six! They should be left in the ringing room, you know.”

“Bird bags?” Savage was momentarily distracted.

“Small cloth bags with a drawstring. We use them to carry the birds from the traps to the ringing room to process.”

“Now, Doctor, I would be grateful if you could give me a detailed account of your movements yesterday evening.”

“Yes, of course. I knew that you would ask me.”

He described the trip from the mainland, the discussion at the supper table, John’s sudden absence, in minute detail.

“I was devastated by Charles’s decision to sell the island,” he said. “Since I retired my work here has been increasingly important to me. It does not only have personal importance, but real scientific value. I felt that it was essential that I should persuade Mr. Todd that our work should continue. I had to show him that without his help the trust would not survive. I thought that if I summarized the accounts, so that he could understand the position more easily, he would be more sympathetic. You must understand that I was engrossed in my task. I certainly had no intention of eavesdropping.”

“But you overheard a conversation which you feel may be relevant?”

“Oh no.” The doctor seemed shocked. “I’m sure that it has nothing at all to do with Charlie’s death. But I feel that it is my duty to tell you.”

He’s enjoying this, Savage thought as Paul Derbyshire repeated the fragment of argument between Jerry Packham and Pamela Marshall. So even distinguished doctors enjoy a good gossip. The thought saddened him. He felt let down.

“You’re quite sure of Mrs. Marshall’s words?” he interrupted. “They were having a row, then she said: ‘If you haven’t got the nerve to do it, I have.’”

“Quite sure, Superintendent.”

“What do you think she was referring to?”

“As I’ve explained, I don’t know. I really was concentrating on the accounts.” There was a strong trace of regret in his voice and Savage believed him.

“What did you do yesterday evening, after Mr. Packham and Mrs. Marshall had left the common room?”

“I decided that I should go to see Charlie Todd to explain to him the enormity of his suggestion.”

Savage’s face and voice betrayed no interest. “ So you saw Mr. Todd last night?”

“No, Superintendent, I did not. If you will allow me to explain. I decided that I ought to see him. I even went upstairs to change into more suitable clothes. Then I noticed that it had started to spot with rain, and it occurred to me that I could just as easily talk to him in the morning. It looked most unpleasant outside. I returned to the common room.”