For work, The Flea wore a plain coat over a blouse and skirt, but her hat had ‘Health Visitor’ embroidered across the band. She exchanged it for a felt cloche in the public lavatory at St Pancras, pausing for a moment between hats to marvel at the shortness of her hair. It hung just below her ears – more of a bob than a shingle (she had rather lost her nerve in the barber’s chair) – but, nonetheless, it was nearly eight inches shorter than before, and the novelty was still delightful. ‘I should think I gain nearly twenty minutes of useful time a day,’ she’d said to Mattie, ‘what with all the washing and brushing and pinning.’

‘It isn’t time that I begrudge,’ remarked Mattie, whose own hair, plaited, had the thickness of a steel hawser, and who harboured a secret suspicion that, like Samson, she might pay physically for its removal; she wore it pinned into a great silver wheel that framed her head.

The Flea’s own hair was limp and fine, dark brown threaded with grey, and the shorter length made her pointed little face appear almost girlish. I shall never grow it long again, she thought, and the idea was quietly thrilling.

The red-headed girl’s name was Ida Pearse. ‘But I’m afraid she no longer works here,’ said the supervisor at the first-class ladies’ cloakroom, mouth pursed, as if balancing a marble on her tongue. ‘She kept getting styes, and that’s not at all nice for our ladies to see, is it? So last week I had to ask her to leave.’

‘Could you tell me where she lives? She … she left her umbrella at our house.’ Even to her own ears this sounded implausible – she had always been a poor liar – but the supervisor was scarcely listening; after one glance at The Flea, her gaze had slid past in search of someone more obviously first class.

‘I couldn’t tell you, I’m afraid. Excuse me.’ She plunged forward with a sudden smile as a customer approached, and The Flea was left standing beside the counter. The waiting room behind it was beautiful: a leaf-patterned carpet, and leather sofas; frosted glass in the window, a central table with a sheaf of magazines and a bowl of potpourri.

In one corner, a girl in a maid’s uniform stood beside a small table, ready to hand out pins, or hairgrips or hand cream. The Flea caught her eye and gave an encouraging smile, and after a moment of hesitation, and a glance across at her supervisor, the girl came over to the counter. She was about fifteen, plump-faced, her eyes like buttons on a pink cushion.

‘Can I help you?’

‘Do you know Miss Pearse’s address?’

‘Miss Pearse?’

‘The red-headed girl who worked here.’

‘Oh, Ida.’ She bit cautiously on the name as though it were an over-seasoned pudding. ‘She had to leave.’

‘I know. Styes.’