Bolted to one of the columns was a splintered piece of wood so old it was black and stone-like. A corroded plaque told me it was a piece of the ‘original Roman bridge over the Thames that once stood close to this site’. I stepped back and looked at it with more respect. Roman. Julius Caesar might have cast an eye over this same piece of wood. He might have leaned on it when it was part of the bridge, talking to someone, or waiting for someone, or scratching the nits in his hair.

This thing was two thousand years old. In Australia, it would be behind glass in a controlled atmosphere. Machines with flickering needles would be monitoring the humidity. Strings of children would be trailed past it. They’d be invited to marvel at the fact that those adze marks had been made by someone whose mother tongue was Latin.

Here, it was bolted roughly to the side of the porch, held up with steel brackets, out there on the street with the traffic roaring past a few steps away.

Was there so much history in Britain that it could be treated casually? There weren’t enough glass cases to hold it all. Was it a more transparent history, too, with none of the uneasiness that I was feeling about Solomon Wiseman?

I looked around and saw one of those ornate black-and-white church clocks high up on the wall. I stared at it, and was just working out that it said a quarter to five, when a voice spoke right into my ear from behind: quiet, pitched to slide underneath the hysterical traffic.

‘Nice old clock, isn’t it?’

I hated him even before I turned and saw him. He was shortish, with receding crinkly sandy hair and one eye higher than the other, a Punch-and-Judy sort of face, features somehow too prominent, his eyes too wide open.

He was obviously a crazy. What other sort of man would come up and speak into your ear like that?

The street was suddenly empty of another human soul. The river of traffic wouldn’t be stopped by someone running out and calling for help. I was frightened.

I reminded myself that I didn’t have to be mild-mannered Kate Grenville, respectable wife and mother, courteous to all. I could be anyone I pleased here on Lower Thames Street.

Abrupt, right into his face, I said, ‘Do you know where Three Cranes Wharf is?’

He was startled. Took a step back. ‘More or less,’ he said after a moment. He was watching me curiously now, as if I were the strange one.

‘Well, where is it?’ It was exhilarating being this rude.

‘Too complicated to explain,’ he said. ‘But it’s down there.’

I didn’t believe him. He wanted to lure me into that shadowed alley. I started to move away.

‘No,’ he called. ‘Down here.’

I hesitated and we stood staring at each other.

He was wearing one of those speckled rubbish-coloured jackets, with a checked shirt and the kind of tie that doesn’t go with anything. His trousers bagged at the knees. He carried a worn and empty-looking briefcase of the old-fashioned kind with a flap over the top. His forefinger was curled around it as if to keep it from springing open, even though this briefcase would never spring open but only sag from its handle.