The Twelve Elms Centre was a pleasingly gothic building, with white windowsills shining against dark grey brick, and all the more imposing under a sky filled with rain clouds. Heather walked up the path through the gardens, noting that they were well kept and neat, while the sign outside the building was narrow and discreet: ‘Twelve Elms Centre for the Treatment of Anxiety Disorders and Trauma’. Inside a cosy reception area she spoke to a sturdy-looking man with kind eyes, who shortly introduced her to Dr Parvez.

‘You’re here to visit Anna Hobson?’

Dr Parvez was a tall, willowy man with an advancing bald patch and large, old-fashioned glasses. He wore a beige cardigan that was both too long and too big for him, making him look a little like an absent-minded grandma.

Heather smiled. ‘Yeah, a favour for my friend Pamela. She used to visit quite often, I think, but has been rushed off her feet lately. You’ve probably met her?’

‘Ms Whittaker, yes. Well, thank you for taking the time. Anna doesn’t get many visitors, and they really do help. News from the real world always goes down a storm.’

He led her down a series of pleasant corridors, all smelling faintly of disinfectant and floor polish. Heather caught sight of a few people here and there: a young man with an old-fashioned haircut reading a newspaper, an older lady sitting in an armchair, rubbing her hands together over and over.

‘Did Ms Whittaker tell you much about Anna?’

‘Not so much. Only that she’s been through a tough time.’

Dr Parvez nodded seriously. ‘She has, at that. She might lose her train of thought a little, but generally Anna is delightful company. Here you go.’

He stopped at the doorway to a wide, spacious room, tastefully decorated in magnolia and a faint, anaemic pink. There were several tables, each set with pairs of chairs, and a handful of people talking quietly. The tall windows looked out across the gardens. Despite the pleasantness of the surroundings, Heather found herself thinking about her visits to Belmarsh to see Michael Reave.

‘The people here,’ she said suddenly. ‘They don’t have … a history of violence or anything, do they?’

A flicker of annoyance passed over Dr Parvez’s face, and Heather immediately regretted asking.

‘We treat a variety of problems here, Miss Evans – depression, anxiety, various personality disorders – and one of the few things they all have in common is that the patients are much more likely to hurt themselves than anyone else. Shall I introduce you to Anna?’

He took her over to a table in the far corner. Sitting there was a tired-looking woman with lank brown hair and a deeply creased face. Heather found she could not guess at how old she was; she seemed all ages at once. She was wearing a soft hooded top and a grey T-shirt, and she looked up at Heather with watery eyes.