‘That’s fascinating,’ Angus exclaimed.

They followed Hedley into the house and up the stairs, where he showed them how to get into the inner attic.

‘Goodness, this is a fully fledged operations room!’ Angus exclaimed. ‘You’re right: it’s World War II stuff.’

Mr Preece nodded. ‘Yes. The government set up hidden places like this all over England in the early days of the war, just in case Hitler managed to invade and they needed to fight a guerrilla war. Some of them are still coming to light, they were so well hidden. A good percentage were unknown to the authorities because of bombings that destroyed records or the people who’d set them up being killed. Some were part of separate hush-hush plans, each of which was known only to a few key figures. With the Cold War in the fifties, I suppose they thought they should still keep something in reserve.’

‘I’ve never heard even the faintest whisper about this one in the family.’

‘They probably weren’t told. When did you get the houses back?’

‘The end of the sixties, I think.’

‘That figures. I’ll leave you to report this find to the Ministry of Defence. I’ll send you my bill with the written report.’ He turned away, taking his torch with him.

Angus followed. ‘I’ll see you out. Do you want to wait for me here, Nell?’

‘Yes. I’m dying to look round this room properly.’

‘I’d better nip back to the big house and fish out a couple of torches. You don’t get a lot of light into the attic through this door, however wide you open it.’

When Angus rejoined Nell, he handed her a torch. ‘Where do we start?’

‘Does it matter? I suppose we’d better not move things, so we can only look.’

‘We could open drawers and cupboard doors if we’re careful.’

The papers they found were yellowed and nearly everything was thick with dust. After a while Nell sighed. ‘I think we’d better leave this to the experts and lock the place up carefully. It could be an important piece of British history.’

Regretfully, they closed the door of the secret room again and made sure nothing indicated an opening there before going back downstairs.

‘Dennings never ceases to amaze me,’ he said. ‘What other secrets do you think it’s hiding?’

‘I don’t know, but if we spend our lives here, we’re bound to find some of them, aren’t we? Do you want to look round the other houses?’

He glanced at his watch. ‘Not today. I’ve got work to do. Um, I’d better tell you more about my mother.’

‘You haven’t said much about her.’

‘I hardly ever see her. She’s in Spain and she hasn’t forgiven me and my daughter for making her into a great-grandmother. She’s very well preserved for her age, spends a lot of time and money on her appearance.’

‘And her second husband?’

‘He was American and suited her much more than my father did. Unfortunately Myron died suddenly last year so she was widowed for a second time. It sounds as if she’s met someone else and apparently this guy is even richer than Myron, so I bet she’ll marry him next. She comes to London every now and then to do some shopping and I usually go up to meet her.’