‘Yo, Logan,’ I wrote. ‘Yo, Logan Mountstuart, vivo en la Villa Flores, Avenida de Brasil, Montevideo, Uruguay, America del Sur, El Mundo, El Sistema Solar, El Universo.’

These were the first words I wrote – or to be more precise, this is the earliest record of my writing and the beginning of my writing life – words that were inscribed on the flyleaf of an indigo pocket diary for the year 1912 (which I still possess and whose pages are otherwise void). I was six years old.

It intrigues me now to reflect that my first written words were in a language not my own. My lost fluency in Spanish is probably my greatest regret about my otherwise perfectly happy childhood. The serviceable, error-dotted, grammatically unsophisticated Spanish that I speak today is the poorest of poor cousins to that instinctive colloquial jabber that spilled out of me for the first nine years of my life.

Curious how these early linguistic abilities are so fragile, how unthinkingly and easily the brain lets them go. I was a bilingual child in the true sense, namely that the Spanish I spoke was indistinguishable from that of a Uruguayan.

Uruguay, my native land, is held as fleetingly in my head as the demotic Spanish I once unconsciously spoke. I retain an image of a wide brown river with trees clustered on the far bank as dense as broccoli florets. On this river, there is a narrow boat with a single person sitting in the stem.

A small outboard motor scratches a dwindling, creamy wake on the turbid surface of the river as the boat moves downstream, the ripples of its progress causing the reeds at the water’s edge to sway and nod and then grow still again as the boat passes on.

Am I the person in the boat or am I the observer on the bank? Is this the view of a stretch of the Rio Negro where I used to fish as a child? Or is it a vision of the individual soul’s journey through time, a passage as transient as a boat’s wake on flowing water? I can’t claim it as my first reliable, datable memory, alas.

That award goes to the sight of my tutor Roderick Poole’s short and stubby circumcised penis, observed by my covertly curious eyes as he emerged naked from the Atlantic surf at Punta del Este, where we two had gone for a summer picnic one June day in 1914. I was eight years old and Roderick Poole had come to Montevideo from England to prepare me for St Alfred’s, my English prep school.

Always swim naked when you can, Logan, was the advice he gave to me that day, and I have tried to adhere to it ever since. Anyway, Roderick was circumcised and I was not – which explains why I was paying such close attention, I suppose, but doesn’t account for that particular day of all others being the one that sticks in my mind.

Up until that precise moment the distant past of my earlier years is all vague swirling images, unfixed by time and place. I wish I could offer up something more telling, more poetic, something more thematically pertinent to the life that was to follow, but I can’t – and I must be honest, here of all places.

The first pages of the lifelong, though intermittent, journal that I began to keep from the age of fifteen are missing. No great loss and, doubtless, like the avowals that begin almost all intimate journals, mine too would have commenced with the familiar deter­mination to be wholly and unshakeably truthful.

I would have sworn an oath to absolute candour and asserted my refusal to feel shame over any revelations which that candour would have encouraged. Why do we urge ourselves on in this way, us journal­ keepers? Do we fear the constant threat of backslide in us, the urge to tinker and cover up?

Are there aspects of our lives – things we do, feel and think – that we daren’t confess, even to ourselves, even in the absolute privacy of our private record? Anyway, I’m sure I vowed to tell the truth, the whole truth, etc., etc., and I think these pages will bear me out in that endeavour. I have sometimes behaved well and I have sometimes behaved less than well – but I have resisted all attempts to present myself in a better light.

There are no excisions designed to conceal errors of judgement (‘The Japanese would never dare to attack the USA unprovoked’); no additions aimed at conferring an unearned sagacity (‘I don’t like the cut of that Herr Hitler’s jib’); and no sly insertions to indicate canny prescience (‘If only there were some way to harness safely the power in the atom’) – for that is not the purpose of keeping a journal.

We keep a journal to entrap that collection of selves that forms us, the individual human being. Think of our progress through time as one of those handy images that illustrate the Ascent of Man. You know the type: diagrams that begin with the shaggy ape and his ground-grazing knuckles, moving on through slowly straightening and depilating hominids, until we reach the clean­ shaven Caucasian nudist proudly clutching the haft of his stone axe or spear.

All the intervening orders assume a form of inevitable progression towards this brawny ideal. But our human lives aren’t like that, and a true journal presents us with the more riotous and disorganized reality.

The various stages of development are there, but they are jumbled up, counterposed and repeated randomly. The selves jostle for prominence in these pages: the mono-browed Neanderthal shoulders aside axe-wielding Homo sapiens; the neuras­thenic intellectual trips up the bedaubed aborigine.

It doesn’t make sense; the logical, perceived progression never takes place. The true journal in time understands this fact and doesn’t try to posit any order or hierarchy, doesn’t try to judge or analyse: I am all these different people – all these different people are me.

Every life is both ordinary and extraordinary – it is the respective proportions of those two categories that make that life appear interesting or humdrum. I was born on the 27th February 1906 in Montevideo, Uruguay, the sea-girt city on its bay in that small country wedged between beefy Argentina and broiling Brazil.

The ‘Switzerland of South America’ it is sometimes dubbed and the land-locked associations of that comparison are apt, for, despite their country’s long coastline - the republic is surrounded on three sides by water: the Atlantic, the vast estuary of the River Plate and the broad Rio Uruguay - the Uruguayans themselves are defiantly non-seafaring, a fact that has always warmed my heart, divided as it is between seadog Briton and landlubberly Uruguayan. My nature, true to its genetic heritage, is resolutely divided: I love the sea, but I love it viewed from a beach - my feet must always be planted on the strand.