Husband? I remembered Michael talking about his father’s vision of the future – the British Empire reborn under a leader like Hitler – and then I was furious with myself: why had I not considered the possibility that Mrs Baron might share the same views? Michael had been brainwashed into his way of thinking by his very own parents.

I have to stop her. I took a deep breath and tried to lift myself up in the chair, but my arms felt almost as numb as my legs. I screwed up my face and willed myself to move, but all I could manage was a feeble wobble before I collapsed into the chair again, air wheezing in and out through my throat, tight with terror.

Mrs Baron laughed. ‘What was I worrying about? I won’t need to chloroform you at all, will I? You’ll be a good girl and stay right there, won’t you?’ She hummed part of the national anthem, then stopped and laughed again. ‘Let’s play musical statues, Petra!’

I gritted my teeth and managed to get one of my arms up on to the ledge of the window behind me, but it was no good – the rest of me was rubbery and useless. I couldn’t go anywhere. I searched around the room frantically, looking for something I could grab or throw, but there was nothing. The only thing I could see that might possibly help me was just beyond my reach.

Mrs Baron stood back, admiring the optic as it spun soundlessly around. ‘And the best thing is that your family will get the blame for this!’ she said. ‘Who would suspect the ARP warden of operating the lamp in the lighthouse? I’m the one who goes around telling people to put lights out!’ She took hold of the lever for the lamp and pulled it down hard with both hands. Light exploded out like a white-hot harpoon.

‘Mrs Baron!’ I shouted, covering my eyes from the sudden glare. ‘There are enemy planes out there – you’re lighting up the whole coastline for them! They could attack the lighthouse—’

‘Tonight’s dogfight is just a diversion,’ she said coldly, and the light flashed around and around her head like a hellish halo. ‘And, anyway, even if we were caught in the crossfire, it would be worth it. I’ve been waiting so long for tonight. Sacrifices have to be made in wars. Your mother, for example – she was a sacrifice.’