I stand stock still, listening. The water I have just waded through settles and calms behind me. A drip in the distance falls from brickwork and plinks daintily into a dark pool far ahead. Apart from that, there is no sound, so I set off again. I slop through the channels of another three or so arches, maybe. I don’t know; I lose count.

‘Dad?’ I am exasperated now, almost beginning to laugh at the sheer idiocy of this. What am I doing down here? How did I get here? I am as far from the comfort of The Palladian as I have ever been. I am wondering at the folly of Dad and me stepping out in the world, if this is where we were going to end up.

‘Prue?’

It’s faint, but that’s definitely my name echoing up through the never-ending arches.

‘Dad!’

‘Here!’ comes the faint cry.

I set off again. A calf-sodden and ineffective Nancy Drew. A woman with as much derring-do as a slug on a biscuit. The water is a little deeper and definitely colder as I trudge on. The air is damp and so musty now you could slice it with a bread knife; the smell of wet bricks and Victorian enterprise is thick and claggy. As I slop through the opaque water, it gets gradually darker, too, but the decreasing light from the hatch at the far end of the tunnel is still enough to show me the way. There are so many arches; I can’t see their end.

‘Dad! I’ll be with you soon!’ I shout at the top of my voice, after I’ve trudged across several more thresholds and navigated more silken pools of blackness.

‘OK!’ a voice echoes back.

I keep walking. My jeans are soaked up to just below the knee now. The further I get from the oblong skylight of the hatch, the harder it is to see anything at all, but I can just about see the end of the tunnel now, in the gloom. There’s some writing on the brick wall there, but nothing that I can make out. At least the tunnel does have an end, I think.

I walk three or four more arches. My feet are very cold now; my shins numb. I am far from the hatch and the real world, and I feel I have been down here for ever.

‘Dad!’

‘You’re nearer,’ he shouts. ‘I’m pretty sure I’m at the end of the tunnel, right-hand side.’

‘Just keep calling, so I can find you.’

‘OK!’

‘Are you all right, though? Where’s Kemp?’

‘I don’t know! But I’ve hurt my ankle. I can’t stand on it.’

‘OK, I’m coming!’