'You clumsy bastard. Dad!' Warren fell back, dropping the torch, ramming a knuckle into his weeping eye, hearing masonry crumbling where he'd staggered and kicked out. If he made it to college without being registered disabled through living in this broken-down pile of historic crap, it'd be a real achievement.

'Come on. Warren, don't mess about! I need that light.'

'I'm f… Hang on, Dad, I can't flaming see.' Hunched in the fireplace, scraping at his gritty, watery eye.

And it was then, while picking up the torch – flashing it on and off to make sure the bulb hadn't broken when he'd dropped it – that Warren found this little tunnel.

It was no more than a deepish recess in the side wall of the fireplace, about eighteen inches off the ground. Which would have put it on a level with the top of the dog grate, when they'd had one. Must have been where he'd kicked back with his heel, hacking off a cob of sixteenth-century gunge.

Warren shone the light into the recess and saw what looked like carving. Put a hand inside, felt about.

Hey, this was…

'Warren! What you bloody doing down there, boy?'

Quickly he shoved bits of brick into the opening, ramming them tight with the heel of his trainer. Then shone the torch back up the chimney for the old man pretty damn fast.

In fact, for the rest of the day he'd been a very willing labourer – 'You stay there, Dad, I'll get it.' 'Want me to mix the cement down here and pass it up, Dad?' 'Cuppa tea, Dad?' Anything so the old man'd get the job done and bugger off out of the way.

The old man had been surprised and pleased, grinning through a faceful of soot, patting Warren on the shoulder. 'We done a good job there, boy. He won't set on fire again, that ole chimney. Fancy a pint?'