‘I don’t know what you’ve been watching on the video,’ Steph continues, ‘but I think I can shed some light on what happened that night.’

‘And let me guess: you have a different cause of death?’ Craig asks.

‘No, no,’ Steph replies. ‘Cause of death is exactly right. Exsanguination from an incision to the carotid artery. Sharp bled out in minutes.’

‘So why are we here?’ Craig snaps, exasperated.

Robin is confused, too, and opens the file. He watches as Steph sits down on the empty hospital bed. She’s taking her time, wanting to get the message across in the right way.

‘While my findings don’t contradict those from the first post-mortem, it’s my more detailed enquiries that I want to share. As doctors, we’re as guilty as anyone of confirmation bias: so blinded by the obvious that we don’t look any further. To the other smaller details that might also be pertinent to the case.’ Steph opens the folder in her hand. ‘So, with this in mind, I did a full and comprehensive review of Simon Sharp’s body, and I found a few other interesting features.’

The whole room is silent, all four police officers waiting for Steph to speak.

‘On first examination,’ she continues, ‘I noticed a large amount of laryngeal and pulmonary oedema. Fluid in the tissues of the neck and damage to the lungs,’ she adds, and Robin knows she must be hugely simplifying what she’s found. ‘Plus, obstruction to his airway caused by oedema and mucous plugging.’ She looks at them all. ‘When Simon Sharp died, he was having massive problems breathing, and that’s if he was managing to do so at all.’

Robin remembers the staggering around on the video, Simon looking like he was choking.

Craig scowls at Steph. ‘So would I, if I had a knife wound to my neck.’

Steph shakes her head. ‘No, I believe this was prior to the exsanguination. To confirm my hypothesis, I tested his blood: he had raised levels of mast cell tryptase.’

Robin watches as Steph takes in their blank faces. ‘Just before Simon Sharp died, he was experiencing anaphylactic shock.’

‘An allergic reaction?’ Craig stutters. ‘To what?’

‘I went back over his medical records. Simon Sharp had an allergy to peanuts. And looking at his stomach contents, he was eating something that looked like a sandwich before he died.’

‘We know he did,’ Robin replies. ‘We saw it on the video.’ He grabs his bag, pulling the file out and rifling through the pages. He pulls out a crime scene photo and puts it in front of them; two plates lying on the side. ‘See here. But surely he would have known that, and been careful? Carried an EpiPen or similar?’

‘Not all allergy sufferers carry an EpiPen,’ Steph replies. ‘And he might not have realised how serious it was. Severity can change over time. Even a tiny amount could induce a reaction.’