It was Friday night in London’s Jewish East End. Across four miles, from Cheapside to Blackwall, the bells of St Mary-le-Bow were ringing. As the city sweltered in the evening smog of high summer, the East End began to close up shop.

Young yeshiva bochers migrated to synagogue in black-clothed droves, released from rabbinical study to bring in the Sabbath. A frenzied whistle stabbed the air as the last omnibus left Whitechapel. Fruit-hawkers and florists loaded up donkey-drawn wagons with pears and peonies and the market squares gradually emptied. Meanwhile, the pubs were filling up with day-labourers, chimneysweeps and men of the docks, knocking back the first of many pints as twilight congealed in a thick haze at the window.

Teetering over Whitechapel Road – that squalid thoroughfare of jewellers, sponging houses and struggling artisans – was a narrow three-storey house. It perched precariously above a tailor’s, where a sign was hanging: Canaan & Sons.

From the outside, it looked unremarkable. Just another worse-for-wear abode belonging to some humble craftsman and his small family enterprise. But inside was a different story: a home bursting with the benign chaos peculiar to Jewish households on the Sabbath eve.

Tonight, one question was on everyone’s lips. A familiar question, but no less urgent: Where’s Benjy?

It echoed up and down the house. From the dusty workshop in the basement – cluttered with half-made suits, mottled mirrors, treadles and needles, bobbins and fabrics – up to the shuttered shop on the ground floor. Through the kitchen swirling with steam and the scent of chicken broth, where the matriarch Ruth was cooking up a storm. Then up the rickety stairs lined with miniature watercolours from the Bethnal Green flea market. And finally, to the very top of the house: that mysterious attic-room which nobody but the absent Benjy was permitted to enter.

Grandfather Tuvia sat in a leather armchair in the living room: his fireside throne. He was an odd-looking fellow – short and stooped, with an unusually full head of white hair. Strangest of all was the pinkish scar that ran along his chin, just under his lower lip, which was curled into a smile as he sucked on a pipe and squinted at the Jewish Chronicle through thick spectacles. Next to him was his wife of fifty years: Hesya, deftly knitting a scarf without so much as looking at her fingers.

‘That boy will be the death of us, lovie,’ she intoned mourn-fully, in Yiddish.

‘Speaking of death,’ Tuvia replied, ‘guess who’s pushing up daisies.’

‘Who?’

‘Rudolph Zemmler.’

Hesya set down her knitting. ‘Rudolph Zemmler? But he was in such good health! He swam fifty laps of the baths at Goulston Square every Sunday. How did he die?’

‘Heart attack,’ Tuvia tutted. ‘Forty-ninth lap.’

‘What a brilliant man!’ Hesya sighed dreamily. ‘And a mensch to boot. He looked after himself. Not like you with your smoking.’

‘“He looked after himself”? He’s dead!’ Tuvia barked – then, in an apologetic undertone, ‘May God rest his soul.’

‘You’re just jealous because he was tailoring for Cabinet ministers while you were out hawking schmutters to yidden fresh off the boats!’

Tuvia shook his head. ‘Rudolph Zemmler was like all those Viennese types: looking down his nose at us Litvaks. What’s more, he was a chancer. Like when he never showed up for my seventieth – “sick with scarlet fever” – but was sitting on his tokhes at the races the very next day!’ Tuvia puffed on his pipe in indignation, then convulsed in a fit of coughing. He was feeling a little sorry for himself. ‘Pah! Next it will be me.’

Hesya took her husband by the hand. ‘May you live to a hundred and twenty, my love,’ she said, pecking him on the lips.

‘Bobba! Zeyde! You’ll get the flu!’ A waif of a girl, no more than six, was standing in the doorway, hands on her cheeks in an expression of utter shock.

‘Nonsense, Golda,’ Tuvia said merrily. ‘Kissing is the cure!’

Golda took a few cautious steps towards her grandparents, twirling her black locks. ‘Mama’s asking if you’ve seen Benjy…’

‘Benjy, Benjy!’ Tuvia cried, ‘How could I see Benjy when I’m marinating like a pickled onion in this farshtinkener chair?’

Ruth appeared behind Golda, red-cheeked and flustered, wiping chicken fat onto her apron. ‘Papa, have you seen Benjy?’

‘Why would you send the child if you were going to ask me yourself?!’

‘Why do you always answer a question with a question?’

‘I haven’t seen Benjy! Now leave me alone! Can a man not read his newspaper, Erev Shabbos, without interruption?’

Ruth retreated to the kitchen to finish dinner before her father launched into another one of his tirades. A bespectacled eleven-year-old boy was sitting at the kitchen table, sipping chicken broth as he pored over a notebook filled with numerical scribblings.

‘Max!’ she shouted, and the boy jumped out of his skin, ‘I told you to go find your brother!’

‘But Mama, I’m looking for a way to help Papa reduce his expenditure! Anyway, Benjy is always late and evidently not home.’

‘Don’t give me lip. “Evidently”! For all we know he’s already snuck in and is hiding in that den upstairs. Why don’t you make yourself useful and go check?’

Max traipsed off. Benjy causing problems again! Did they not realise that Max was cracking something infinitely more important than his delinquent older brother? Nobody dared talk openly about it, but the business was in dire straits: running at a loss, with expenses mounting and turnover dwindling. For the past week, Max had devoted himself to tallying up the costs of fabrics – cashmere, cotton and crêpe, tweed, twill and toile – and coming up with a plan to economise.

His theory went like this. Currently, his father was buying overpriced muslin and fine calico by the pound from those miserly Ganguly brothers in Spitalfields. Max calculated that it would be more efficient to buy cheaper fabric in bulk from the wholesalers up in Dalston. His father objected that this would compromise the quality of their garments.

But Max had seen the kind of business those slopsellers were attracting – the ones making enough money to leave Whitechapel for Kensington and Islington – and it was not because of their superior craftsmanship. It was because they had the one thing that all the retail bigshots at synagogue murmured about: scale. If his father hired junior tailors with his disposable income (plus a bank loan for short-term capital if needed), he could create more product and give the shop real volume—

‘Haven’t you heard of knocking, you nosy thing?’

Max came to his senses. His older sister Judit, with her bright crop of ginger hair, was lying on her bed, clutching a sheet of paper to her chest.

He could tell from her blush that the letter was to Jack Hauser: their father’s apprentice – a prattling langer loksh who could juggle five apples in one go and took her to the music hall most Saturday nights.

‘Is Benjy in here?’ he asked.

Judit’s cheeks were burning. ‘Hmm, let me check…’ She looked under the pillow. ‘Not here.’ She opened the drawer next to her bed. ‘Not here either.’ She peeked down her blouse. ‘And not here. I guess that means that Benjy must be elsewhere! Maybe you should check the races, the boxing club – or Newgate Prison!’

Max rolled his eyes. ‘Now, now, there’s no need to be facetious.’

Judit flared up – ‘What did you call me?!’

‘It means “to treat a serious issue with flippancy”! I read it in the dictionary.’

‘Never mind! Listen, I need you to do something for me.’ She folded the letter and offered it to Max. ‘The next time Jack Hauser comes round to run his errands, you are to give this to him. Got it?’

Max’s hand was hovering over the letter. ‘Oh really? And what’s in it for me?’

‘The good fortune of not having your backside whipped!’

Max was still sceptical.

‘And a block of Mr Benady’s toffee,’ Judit added.

‘Done!’ Max snatched the letter, stuffed it in his pocket and scampered out.

No sooner was he gone than Judit let out a happy sigh and fell back on her bed. For two months now, practically from the day that Jack had loped through their front door, he and...