‘What did the locals think about the magic?’ I asked, thinking of my mum, who has definite views about spells, witches and where they fit into a well organised society – i.e. not around her.

‘These were tribesman,’ said Lady Helena. ‘They already believed in magic. I don’t think they saw anything strange in it – even if we were wazungu.’

They were much more enthusiastic about her mother’s ability to set bones and treat injuries. Nightingale asked where she’d learnt those particular skills.

‘The basics were handed down,’ said Lady Helena. ‘But she refined the techniques working on her animals.’

‘What about the natives?’ I asked.

Lady Helena glared at me and then looked away.

‘You have to understand,’ she said, her eyes on Nightingale. ‘There were no hospitals or clinics nearby – she couldn’t turn people away.’

Nightingale nodded understandingly.

There were limitations to what her mother could do. Gross physical damage, broken bones, cuts and abrasions were easy enough. But not diseases or chronic conditions.

‘Cancer,’ said Lady Helena bitterly. ‘Obvious tumours she could excise and then promote healing at the site. But she couldn’t reach anything systemic. Including her own leukaemia.’

She hadn’t told her family either, until it was too late for chemotherapy.

‘This was after the Emergency,’ she said, ‘after we’d moved to Uganda.’

I wanted to ask what kind of formae her mother had used to knit bones and heal tissue, but Nightingale had discussed this with me in advance.

‘Please try not to be distracted by the details, Peter,’ he’d said. ‘We want to know about her connection to Fossman and what she knows about the Faceless Man. If all goes well, there’ll be plenty of time to satisfy your curiosity later.’

My curiosity? I thought, as Lady Helena talked about bones healing in days not weeks. Dr Walid’s going to break his Hippocratic oath and kill us because we didn’t invite him along. Thank god I’ll have the recording to keep him sweet.

After her mother died, her father packed her off to posh school to finish her education. But this was London in the sixties and there was no end of mischief a fearless young woman could get up to in those days. Stripping off for David Bailey was the least of it.

‘You know the list, darling,’ she said to Nightingale. ‘Sex, drugs, rock and roll. But of course I found myself drawn into what they call the demi-monde.’ She looked at me. ‘French for half-world,’ she said, obviously unaware of the existence of Google. ‘A bit more exclusive in those days, less fashionable.’ She grinned. ‘Less safe.’

She met a young man called Albert Woodville-Gentle there, who could do magic.

‘Not as well as me,’ she said. ‘He was all bash, bash, bash – no finesse.’

‘You were lovers?’ asked Nightingale.

‘On occasion,’ said Lady Helena. ‘When the mood took us.’

‘Friends with benefits,’ said Caroline.