‘The polka? What does he think I am, a damned foreign revolutionary? He is lying in his teeth, if he has any. He is simply trying to make me pay for his own clumsiness. It was not a polka at all. It was a waltz, and a waltz never hurt anybody.’

While he was saying this, Collis was signalling to Kathleen Mary that she should open the sashed window. She didn’t understand his frantic mime at first, but when he hissed at her, ‘The window!’ she nodded, and went across to unfasten it. A fine drizzle was still falling, and the parapet outside was glossy and wet.

‘Can’t you just pay for the damage?’ Kathleen Mary whispered. ‘It can’t be very much.’

‘Of course I can,’ Collis retorted. ‘But it’s much more entertaining to slip out from under their noses, and leave them unpaid.’

The doorhandle was rattled again, and this time it was the proprietor of the Madison who spoke. ‘I’m not alone out here!’ he called, in his contralto voice. ‘I’ve brought two bruisers to make sure I’m paid!’

‘I’m afraid that’s true, Mr Edmonds,’ added the hotel manager. ‘There are two gentlemen of no mean size out here.’

‘What’s size, compared to genius?’ called out Collis, and quietly ushered Kathleen Mary to the open window. ‘Climb out on to the parapet,’ he told her softly, ‘and keep close to the wall. You can walk along to the costume makers next door. They’re bound to have their windows open — it’s a hot-house in there.’

‘How do you know?’ Kathleen Mary asked him anxiously.

‘I’ve done this before, my dear, more times than you can count. Now, get going, before the manager unlocks the door. It’s quite safe.’

‘I’m not at all sure,’ said Kathleen Mary. ‘It looks an awful long way down to the ground.’

‘Just go, will you?’ urged Collis. Behind him he could hear the manager’s keys in the door.

He bent down and laced his fingers together so that Kathleen Mary could use his hands as a step. Shakily, with her green dress held up, she clambered through the open window and crouched on the parapet on her hands and knees.

‘Go on!’ said Collis.

‘I can’t,’ she told him in a squeaky voice. ‘I’m frightened.’

The bedroom door burst open, and there was the manager in his tailcoat, and the proprietor of the Madison Saloon, a stocky, bluff fellow with wide whiskers and extravagant eyebrows, and behind them both, looming very large, the wide shoulders and the stony, stitched-up face of a Chatham Square bruiser.

‘Too late!’ Collis grinned and swung out on to the parapet. ‘The phantom table waltzer escapes again!’