You may be forgiven if JR Ackerley doesn’t ring many bells. He was literary editor of The Listener, the great magazine of the early days of the BBC, and liaised with some of the finest writers of the day, including George Orwell, Virginia Woolf, Bertrand Russell and TS Eliot. EM Forster was a close friend, and he had an important role in discovering (among others) WH Auden, Philip Larkin and Christopher Isherwood.

His personal life was unremarkable: a young boy with artistic inclinations, he was born into an affluent household in Richmond, the son of a fruit merchant and a successful actress. He then served as a lieutenant in the First World War, enrolled at Cambridge, and then transferred to London to work for the BBC. From his small flat in Putney, he wrote four novels of good quality but little legacy. A lonely bachelor, devoted only to Queenie, his pet Alsatian. A little eccentric perhaps, but nothing out of the ordinary.

But he left behind a memoir too My Father and Myself, which gutted this carefully-tended image, revealing black-and-white Britain as a colourful and complex world which had been stiffened under the gaze of prissy PathĂ© newsreel cameras. From his school-days to the First World War, inter-war Cambridge to the horrors of the Blitz, Ackerley’s domestic life was in truth a game of masks.

First, Ackerley sketches out his own father’s life, similarly hum-drum and respectable. Born to a Liverpool stockbroker, he left for London and joined the Royal Horse Guards. He served abroad in Egypt, before settling down to a successful business shipping Caribbean bananas. A classic father-figure: outwardly sociable, inwardly reserved, a combination of smiling kindness and ruthless justice. The two lived happily together under the same roof for twenty years, swapping dirty stories, playing cards, sipping port. Without knowing it, over these twenty years both father and son were lying to each other.

In order, Ackerley calmly relates how the birth of his elder brother was an accident, his father having “run out of French letters”, consequently marrying one of his numerous mistresses. His discovery that his father’s ubiquitous “twinges” at the breakfast table was tertiary syphilis contracted on active service in Egpyt. His own secretive life as a homosexual, regularly taking home young policemen, sailors and members of the Household Cavalry. How in his career in the guards his own father was possibly a kept man, the sex partner of a Swiss aristocrat. How upon his father’s death, he discovered a posthumous note, jocularly announcing he had had two daughters by another woman, a second family who had lived just down the road for 20 years, whom he would go to visit on weekends while walking the dog.

Ackerley opts for a non-chronological memoir, weaving backwards and forwards in time, “turning up a little more subsoil” with each sweep. He sets the situation, and without warning smashes it down with a hammer. The shattered remnants of the façade make us look back on the previous chapters and share in Ackerley’s personal experience of memories turning rapidly to dust. We move forward, assuming we’ve found the truth. But this is also a façade, smashed in turn, leading us deeper and deeper into a Russian doll of deceit.

The unflinching handling of the truth is the book’s primary asset. Novelist Will Self thought the book “an exquisite account of social reality in the early 20th century, rather than the Downton Abbey bullshit most writers come up with.” And it’s just that. Closed doors are flung open, with no regard to do not disturb signs. All cards are laid on the table, no matter how grubby. Writing from the safety of 1968, the onset of old age and the abandonment of the censor, Ackerley writes of schooldays when he and his chums cut holes in each other’s trouser pockets, hands sliding straight to another’s groin when classes became uninteresting. After describing the flamboyant overcoat, cravats and Edward VII homburg his brother wore, Ackerley reminisces of the envy he felt of his brother’s extra-long, dark penis fleetingly glimpsed in the showers. It jars when set along the usual period dialogue, laced with the usual quintessential slang – “old chap”, “drat”, “blighty one” – unreal, Three Men in a Boat after the watershed. Our perception of the past is changed.

Introducing the book, Auden questions why the memoir is so morose. Ackerley’s father seems to have been a perfectly kind and tolerant man, one who allowed his son to pursue his artistic talents. But Ackerley’s bitterness is entirely understandable, stemming from happy memories that have been toxified. Upon reading his father’s note, he felt their relationship was ruined. “I had known nothing about him at all.” The family is where pretence and performance is meant to be discarded, slouched off like a hat and coat, revealing the core of the man, both good and bad. His father had never taken off his hat and coat. He had become an insincere “stranger”.

Despite his father’s misguided attempt to “do his duty towards everybody”, Ackerley doesn’t make himself a martyr either. That would not be the truth. If he had been less self-obsessed, perhaps he would have noticed his father’s erratic behaviour. Heroism is left out of the story. In a twist worthy of Journey’s End, his brother arrives for a trench-raiding party in a section of the line Ackerley commanded in 1917. Later his brother lies in no man’s land, fatally wounded. By contrast to Ernst Jünger, of Storm of Steel fame, who dashed through an enemy machine-gun just at the rumour of his brother’s injury, Ackerley does nothing. “Disgusting” as he finds it to relate, he stuck to official policy of not risking lives to rescue one man over the top. He “got along” with his brother perfectly well, but he didn’t love him.

One of the most under-estimated phrases in non-fiction is “I don’t know.” The drive to be authoritative, to have All The Answers, consumes today’s bestsellers, papering over gaps in knowledge with generalizations or diversions. In the effort to stick to truth, Ackerley finds holes in the narrative unavoidable. Memories have faded, traces grown cold. Much of the book, he believes, is “waste-paper”. There is so little he is able to find out about his father’s past – although all the evidence points to his father being a “close friend” of a notorious homosexual of the 1880s, a handsome guardsman at a time when guardsmen were notorious rent-boys, he cannot know for certain if his father had been bisexual. How had his father contracted syphilis in Egypt? How much had his mother, an erratic but charming woman, known of his father’s indiscretions? He doesn’t know. Even though truth is superior to lies, it is elusive and painful, rarely pure, never simple.

Deriding the hypocrisy of a hubristic past is always a morale-boosting entertainment for a self-righteous present. But it draws away from the undeniable fact these acts of social tragedy and human weakness still happen. For whatever reason – respectability, love of family, access to resources, institutionalisation – many hide shameful acts in the need to conform. Ackerley’s story, once the winged collars and spats are removed, could have appeared on the Jeremy Kyle show. For Ackerley, the greatest “heroism” is simply to tell the truth.