‘It’s never to be entered into lightly ‒ condemning a prisoner to death ‒ but if the case is proved, that will be your duty. And, though it be melancholy, you must do it. Each Englishman’s house is his castle, gentlemen. Do your duty, so we may be safe in ours.’

The prisoner knows nothing of the case against her until after her trial starts. You’ve already told me that you’ll be forced to try to cross Jessop’s bridges as he’s building them, and that it will be a scramble to keep up. It’s not fair, of course, but there’s very little that’s fair about Old Bailey justice.

He calls his first witness. Dr Wilkes, the house surgeon at Westminster Hospital. Swollen chest, short legs. A bullish chin that slops over his neck-cloth. He gives me a fleeting look, turns quickly away. I’m here to be gawped at but no one can brave the sight of me for long, it seems. Turning to the jury, he tells them he’s done over twenty autopsies, gives it all the slow weight of a sentence he’ll no doubt have engraved on his tomb. I’ve opened more bodies than that, but it’s prudent to keep that to myself, of course. At about four o’clock that morning, he says, he was called to Levenhall, where he examined the bodies. Mr Benham had sustained deep gashes to the upper and middle chest, and Mrs Benham the same.

He instructed the bodies to be taken to the hospital where he conducted the examinations himself, recording the cause of death in both cases as exsanguination.

‘Later that day, the constable handed me a butchering knife, which he said had been recovered from a cabinet in the bedchamber. It was the same knife produced in evidence and shown to me here. I matched the blade directly to both victims’ wounds.’

‘Did you note anything else?’

He hesitates. ‘Mrs Benham had recently been with child. There were clear signs. Enlargement of the uterus, general flaccidity, oedema of the bladder. A large corpus luteum in one of the ovaries. An apothecary’s jar containing a human foetus had also been delivered to me at the hospital, and I concluded that it was in fact the product of that pregnancy, and about eighteen weeks’ gestation.’

Silence follows those words. A single cough comes from high in the gallery. Pews gleam through clouds of smoke. Jessop lifts the jar. ‘Is this the . . . ?’

You leap to your feet. ‘My Lord! This is outrageous. What is the meaning of bringing that here?’

Jessop turns to the judge. ‘I believe that’s a matter for legal argument, M’Lord.’

‘Which my friend knows full well is not permitted to me. But as a matter of law, since there isn’t a single word about this on the indictment, it can have no place here. Nor, as a matter of law, can a foetus be murdered. That . . . thing is inadmissible.’

The judge shakes his head. ‘Mr Pettigrew, you aren’t alone in finding it macabre. Mr Jessop?’