Except, of course, he did; intent on causing me injury, to doubt the truth that Ethlyn was as commendable as Doc Saunders was despicable in casting aspersions on my mother’s character by attributing to her a sexually transmitted infection that was heavily stigmatised.

Therein lies the rub for the kind of memoir writing I have trafficked in for the past decade. How to distil the truth? My Jamaican family, when they’re not dissembling a story, will tell you straight: ‘Me nuh like people chat me business.’ My relatives are schooled in obfuscation. They withhold stories, and, in any case, under scrutiny, will trot out the Jamaican aphorism: ‘There are no facts, only versions.’ The unreliability of facts permeates Jamaican culture. It is often asserted, for instance, that the laws of the land are written in pencil so they can be easily rubbed out.

How then do I travel, as it were, between the birthmark and the stain?  How do I embrace the simple fact that I was born black, and reject the negative judgment, promoted over centuries, that blackness is  a curse or a stain? Well, I could write as if the reader was part of my extended family, along the way providing linguistic insights to help them navigate the story. Take for example the phrase ‘play fool fi ketch wise’, a strategy practised widely by Caribbean people that is rooted in the days of slavery. When confronted and threatened by the overseer, the enslaved habitually disabused massa of the notion that they constituted a threat by masking their intelligence. It’s a fundamental modus operandi even today, as familiar to black people as the black nod.

Lately I’ve been excited by the prospect of extending the black nod – the subtle signal of recognition and allyship that a black stranger in my youth would give to a fellow black person as they passed each other on the street – to all people, not just those who are black. Writing, for me, is an act of intimacy, giving readers a version of the black nod. Its extension to those not numbered among the black cognoscenti is a gift, I reckon; like a line of credit you don’t have to repay.

I see my non-fiction creative writing as a tribute to black readers as well as those who identify as non-black but might yet recognise the resonance of the protagonist’s epiphany at the end of Ralph Ellison’s Invisible Man: ‘who knows, but that, on the lower frequencies, I speak for you.’

The frequency of my diasporic black family’s language hums with meaning but can be difficult to tune into. When questioned, for example, about whether she considered herself beautiful, Ethlyn would answer in a way that would seem straightforward to us, but perhaps enigmatic to strangers, ‘Tree nah grow in mi face.’ For me, the thrill and challenge of writing is to use that language to reach for, to grasp and illuminate, a truth which has previously been shaded or left to grow inconspicuously in the dark; a photographic negative emerging as a print in the developing fluid, but one that retains its negative capability; its precise meaning not necessarily yet reached.

Still, the language used to describe the Afro Caribbean world in the memoir I’m Black So You Don’t Have to Be, to communicate with readers unfamiliar with the terrain and contours of its culture, comes with a risk. Always I tell myself: yes, you transmit but do they, the readers, receive?

Consider the title – one I rehearsed on the pages of Granta four years ago. Is it a provocation, an insult, a plea for special consideration, or none of the above? Its meaning may not be immediately apparent; it’s meant to leave room for speculation, for the reader to fill in the dots. But then it’s also a statement of fact. In the 1960s, James Baldwin often asserted that hollowed-out white Americans needed their black compatriots in order to define themselves. But here the language is informed by a Jamaican vibe, with punctuation, designed to imbue the reader with a particular sensibility, to become for the duration of the reading, at least, an honorary Jamaican.

In reality, the title is simply a phrase my rambunctious uncle Castus coined to describe my privileged life, earned without merit off the back of his misfortune. He’d arrived in the UK, in the 60s, at an unpropitious, more nakedly hostile time, when the population didn’t see beyond his colour; he was black so I wouldn’t have to be.

The writing is composed as evocation, with language, not just decorating but conjuring a resonant truth, contributing to its hum, its atmosphere. It’s analogous to the way you might sense meaning in music, written in a foreign language, with unintelligible individual words.

In I’m Black So You Don’t Have to Be, that hum is occasionally discordant when Doc Saunders’s language is flecked with brittle notes. And by the book’s end, I hope you’ll be able to discern the difference between the birthmark and the stain.