‘How old d’you reckon I’d be?’ he’d asked me several times.

I always pretended. ‘Oh, seventy? Seventy-five?’

‘Ninety-eight!’ he crowed. ‘Ninety-nine come June!’

After every shower of rain, Old Mr Barnes climbed up a ladder onto the roof of his kitchen—a corrugated iron lean-to on the back of his small house—with a paintbrush and a pot of black stuff. We’d offered to go up for him, but it was a matter of pride with him that he could still get up the ladder, still put another blob of stuff on the bit where the roof leaked.

He was up on his roof today, holding the paintbrush, looking as if he was enjoying the sun. When he caught sight of me getting the washing on the line he called out straight away, ‘Bet you don’t know how I got me nickname!’

‘What nickname?’

It was when he was at school, he told me.

I tried to do the sums and work out what decade it would have been—even which century.

‘There was this bigshot inspector come,’ Mr Barnes called out. ‘Wanted to know how you spelled island, well I told him. I-S-L-A-N-D. Dad worked at Garden Island, see.’

He dabbed the brush at the rusty bit of roof.

‘So he says, “well done son, very sagacious of you.”’ Mr Barnes laughed so hard that I glimpsed his false teeth slip. ‘We all think he’s having a lend of me, but he says, sagacious means wise, son.’

With knobbed old hands he carefully squeezed the lid back on the tin of black stuff. ‘So that’s where it come from. Sagitty. Well, nice talking to you, Um.’

He turned himself around, very slowly, and explored with one foot for the rung of the ladder. I watched him, ready to leap through the plumbago, but he made it down all right. His foot had barely touched the ground when I was in the kitchen writing it down. ‘Sagacious = Sagitty. Change all the names. Find nicknames.’

I knew just where to go for authentic late eighteenth-century names: the convict registers.

‘Anty’, a coal-heaver

John Blackwood

‘Bully’ Dawson

Thomas ‘Hazzles’ Herring

William Nettleship

John Ogle

‘Birdy’ Pidgeon

John Quick

William Thornhill

James Twist

William Underwood

‘Scrummy’ Williams

From ‘the Wiseman character’ it was a short step to William Thompson, then William Blackwood, then William Thornhill.

Changing his name changed my relationship to the character. My great-great-great grandfather had stepped out of the book now, taking his name with him. He had a story, the one I’d found in the archives, but it wasn’t the one I was telling. He watched—sardonically, I felt—as I went on writing in another direction, further and further away from him.