It takes Harriet another half an hour to be admitted into the inner prison. There is another brief conversation to be had with the warder in charge, where she has to repeat her request. She is required to sign her name and tries to ignore her worries about what her parents will say if they discover she has visited a prison. Then she is forced to abandon her handbag on a small shelf. No one searches her intimately or intrusively, but she is asked to turn out her pockets, and an unsmiling female warder runs her hands over her blouse and skirt to make sure that she is not carrying any means of escape for Alice, nor anything that might be used as a weapon. By the end of it all, she feels like a criminal herself. Looking up at the high walls, set with many tiny windows, each one suggesting a cramped cell, Harriet can only fancy that the inmates would long to escape such a place – but she cannot conceive of how it would ever be done.

But then, even this morning, she would never have imagined that she would be standing inside Holloway prison at all. A thrill of excitement pulses through her body. She has never done anything quite so daring.

The female warder leads her under a high-roofed tunnel and into a second, much larger courtyard surrounded by walls that reach to the sky. The courtyard stands empty, save for a few women dressed in dark blue uniforms, similar to the one this warder is wearing. These must be prison staff rather than inmates.

Harriet follows meekly, clutching the notebook and pencil that she has been allowed to bring, as the warder crosses the yard towards a door in the corner. A voice yells something incoherent from one of the high windows. Her presence has caught someone’s attention. Another shout echoes over the yard, and then a third. Harriet cannot hear what they are shouting, but it is aimed at her. Her heart begins to beat harder, and she is aware of a rising terror that’s making every step more difficult.

The warder unlocks the door and ushers her in.

‘They’re edgy,’ she says, rolling her eyes. ‘It’s nearly time for their exercise, and some of them are ready to get out. Ignore them.’

They walk in silence down a narrow corridor. It’s gloomy in here – no wonder the women want to be in the open air. There is a sour smell of unwashed bodies and poor drainage that makes Harriet’s stomach lurch.

They pass ten doors along the corridor before the warder stops and bangs on the eleventh. She slides a small metal trap open, disclosing a window into a cell, and peers through.

‘Dunning, someone to see you.’

‘Who is it? I’m not expecting visitors.’

‘It’s the Church, Dunning. This young lady here’s come to save your soul.’