Billy had been twelve years old when he ferried his first message for a guest at the hotel, and since then he had outlasted one head concierge, three night managers, two grill chefs, one bookkeeper and – as far as he could count – more than three hundred waiting staff, kitchen staff and chambermaids. He had even outlasted Mr Moore, the garage attendant, who had come to the Buckingham as a stable hand and lost no opportunity to talk about how different things used to be in the good old days. Five years after running his first errands, Billy considered himself a veteran of the establishment. Why, he was even longer standing than Lord Edgerton himself – and that had to mean something. It would soon be three years since Lord Edgerton had taken majority ownership of the hotel. The days before seemed a bygone age. Billy had often loitered outside the hotel director’s door in those months before Lord Edgerton had swept in and made the Buckingham his own – and he fancied he knew more about the financial ruin that had once faced the hotel than anyone but Maynard Charles himself. He’d known about the plans to open a ballroom long before the heads of department; he’d even seen the magazines featuring Hélène Marchmont on Maynard Charles’s desk and fancied, before the rumour had even begun, that the hotel board was courting the glamorous star to appear on their dance floor. No, there wasn’t a thing that happened in the hotel to which Billy Brogan wasn’t privy. And that was exactly the way he wanted it to stay.

Tonight Billy stole across the Grand Ballroom as it filled with guests in black silk velvet and cocoa silk chiffon, and slipped into the musicians’ room behind the dance floor. The boys from the band were either lounging around or fastidiously checking their instruments for the performances to come. Behind the practice piano, Louis Kildare, a tall black man, was hunched over his saxophone with Hélène Marchmont at his side.

‘You wanted me, Miss Marchmont?’

When Hélène saw that Billy was standing there, she reached into a clutch bag at her side and drew out a manila envelope, inscribed with two words: NOELLE ARCHER. This she handed to Billy, who almost saluted as he took it in his hands. ‘Tonight, miss?’

‘If you would, Billy,’ Hélène said – and Billy recognised a weariness in her tone that she was trying hard not to let show. ‘Of course, you have my gratitude.’

For a boy like Billy Brogan, gratitude came in the form of a half-crown pressed firmly into the palm of his hand. ‘You have my word, Miss Marchmont.’

The way Billy Brogan said such things, always with an excitable little flourish, made Hélène smile. ‘Be off with you,’ she said, and Billy was beaming as he disappeared.