Callum Bell crossed me. Boy did he cross me. Abandoning his post in my lab to follow his bit of stuff into Physics, I mean how ridiculous is that?! I’d have probably forgiven him for that (I expect he’d have come crawling back eventually), but there was the matter of the substantial funding he was the caretaker of. I am acutely aware that everyone wanted their hands on that money for lots of very worthy and exciting projects. But I needed that money.

I had recently committed myself to secret monthly payments to Sarah Bellamy. Callum got the poor girl pregnant and she was desperate. Us scientists don’t get paid the big bucks and she was only asking for enough to support herself and Callum’s child. But Callum callously refused. And I couldn’t see her suffer, so I decided to pay her - in cash - and say it was from Callum, thinking I’d be fine financially because the donation was definitely coming my way, so my salary was bound to increase.

How foolish was I?

Not foolish enough to kill him, if that’s what you’re wondering. You’ll have noticed, I’m sure, that the person signing out the arsenic in small quantities over the past week or so tried to cover it up by signing my initials, but their penmanship leaves a lot to be desired - nothing like my handwriting! Also, I am a stickler for the rules and at no point is anyone permitted to bring food or drink into my lab. If Callum’s tea was poisoned and the only time I saw him was in my lab, how could I have had access to his cup?