Immediately, other people in the cellar joined in and the air filled with laughter, jeers and cries of delight, as the wall was covered firstly with shadow rabbits and then, following Ray’s lead, birds with flapping wings, dogs and cats.

Oh, blast! He’d been so busy with the shadow puppets, that he’d forgotten something – a vital part of the drill.

‘Gas masks on, everyone!’ Ray shouted, standing up so fast that the bench he’d been sitting on tipped back. He ignored the groans and those who were continuing to meow and bark and, finally, the shadow play stopped. ‘Chin first, then pull them on. Come on! We’re supposed to practise this every day!’

‘Don’t you hate that ’orrible rubbery smell,’ Elsie said, sniffing her mask. ‘Makes me feel quite Moby Dick.’

The airman didn’t have his gas mask with him. It looked as though he were about to help Maggie with hers.

‘Excuse me,’ Ray said, stepping towards them, ‘if there’s a gas attack, she needs to be able to do it herself. Best if you don’t help her.’

The airman put his left hand up in mock surrender and exchanged rueful glances with Maggie.

A huge raspberry sound reverberated through the cellar, as Bill blew on the rubber of his mask, making everyone laugh.

Ray smiled, despite himself. Perhaps it was good for morale. He was in charge of morale, so perhaps he was in charge of laughter too. Even his Nibs’ broad shoulders were quivering, as he put on the child’s Mickey Mouse mask and he was shaking his head, as though laughing at raspberries was against his better nature.

‘I’m all misted up. Can’t see a bloomin’ thing!’ someone said, in a muffled voice.

It was queer, seeing everyone in their masks, suddenly anonymous and looking like mutant beetles.

Ray made them wait a minute or two and then gave the order to take them off. Instantly the cellar was full of sighs and exaggerated gasps for air. Nancy fished around in her handbag and started applying lipstick; Miss Sharp and Elsie fussed with their hair. Honestly, what a to-do. Anyone would think that he, Ray, had personally come up with the rules.

Nancy snapped her mirror shut. ‘Is that it? Can we go now?’

‘You need to sound the “all-clear”, Ray!’ Elsie said.

He frowned. ‘Oh, no. I don’t think that’ll be necessary.’

‘I’ll do it,’ Bill said, holding up the horn. Ray winced and stole a glance at Lord Ashford. He was talking to Mrs Nicholls, so, with a bit of luck, he wouldn’t notice that it was Bill who sounded the horn.

‘It needs to be a different sound though,’ Bill said. ‘One long note for “air raid” and then something else for “all-clear”. How about this?’

He took a deep breath and sounded a long note, followed by three short ones.

The girls cowered, covering their ears.