Some artists are instantly recognisable because of what they paint. Long slender faces: Modigliani. Surreal dreamscapes? Di Chirico of course. Frank Auerbach is part of this camp but not because of motifs or symbols that appear across his work. You can tell an Auerbach because of how he paints.

With a career spanning almost 70 years, his distinctive impasto technique crafting thick layers of paint and highly expressive approach has left an indelible mark on British art and culture. Now a new exhibition at London’s Courtauld Gallery gathers his charcoal heads, large-scale charcoal portraits created as he was starting to gain prominence.

Auerbach was born in Berlin in 1931 to Jewish parents. His father Max had served in the German army during the First World War before becoming a patent lawyer and marrying Charlotte.

Their comfortable bourgeois life in the Berlin suburbs would not last. When Frank was two years old, the first wave of Nazi antisemitic legislation that would gradually but systematically take away Jews’ rights and property was enacted, and his father’s licence to practise as a lawyer was revoked.

Frank Auerbach (b.1931), Head of EOW, 1960 Charcoal and chalk on paper. The Whitworth, The University of Manchester © the artist, courtesy of Frankie Rossi Art Projects, London

A family connection would save his young son’s life. Aware that the Nazi leaders were preparing for war in Europe, the British writer and philanthropist Iris Origo sponsored six children to attend Bunce Court, a newly-established private boarding school in England.

The institution had been founded in southern Germany by the German Jew Anna Essinger, but then transferred to England as Germany’s Jews began to feel the effects of the Nazis’ legislation and decrees. Frank was one of six lucky children who were sent to the school in April 1939, a few months after Kristallnacht, and a few days before his eighth birthday.

Before long, the letters his family sent to Frank at Bunce Court gradually stopped. His parents were murdered in Auschwitz in 1943. They are commemorated in Berlin by Stolpersteine, the brass tiles recording the names of Holocaust victims set in the pavements, in this case outside the building where Frank spent a handful of happy years.

In 2013, in a very rare interview he expressed a remarkably stoic acceptance of his parents’ fate. “I am in total denial…to be quite honest I came to England and went to a marvellous school, and it truly was a happy time. There’s just never been a point in my life when I felt I wished I had parents.”

Frank Auerbach (b.1931), Head of Helen Gillespie II, 1962, Charcoal and chalk on paper. Private Collection © the artist, courtesy of Frankie Rossi Art Projects, London

Frank left Bunce Court at the age of 16. He tried his hand at acting, and was supported in the pursuit by schoolfriends, but soon settled on becoming an artist. After the war he enrolled at the Borough Polytechnic Institute where he came under the tutelage of David Bomberg, another Anglo-Jewish artist and key figure in 20th-century British art.

Bomberg’s Jewish background was very different from his pupil’s. Born in the East End to Jewish immigrant parents, he was fascinated by his rapidly industrialising city. Initially, Bomberg aligned himself with the London-based modernist movement Vorticism, which, with its mechanical vocabulary of hard edges, vertiginous perspectives, sharp diagonals and overlapping planes, attempted to relate art to industrialisation. But after the First World War and scarred by what he had seen, Bomberg favoured an organic approach to painting, and his work in this period is chiefly figurative and painted in thick harmonious strokes.

Bomberg encouraged his students to capture the emotional dynamism of their subjects, to follow their gut instinct rather than ideology, and Auerbach was enthralled.

After the Borough Polytechnic Institute, he went to the Saint Martin’s School of Art and then the Royal College of Art, but Bomberg’s influence over him endured. Unhappy with what he saw as constraining institutional conventions, the young artist rebelled, and found inspiration in the bombed-out rubble of building sites.

Frank Auerbach with a self-portrait (Pilston)

Back in his studio in Earl’s Court, he would reconfigure his sketches of burst concrete, skeletal iron girders and towering cranes onto canvases, layering paint for up to months at a time, often scraping off old sections only to reconfigure them the next day.

His 1956 solo exhibition at the Beaux-Arts Gallery was the first milestone in his career. Showcasing 24 paintings, including his building site landscapes, the show brought his idiosyncratic method to the attention of the critics.

Most were captivated by his exploration of paint’s physicality, and what they saw as the artist’s expression of raw emotion. But others were less convinced. The critic and broadcaster John Berger said he was interested by Auerbach’s use of “thick, uneven, turgid” paint but that it left him unmoved.

The art historian Alan Bowness drew interesting parallels with Chaim Soutine’s expressionist landscapes in which nothing is stable, and everything is swept up in a desperate vortex of thick paint and manic brushstrokes. Like Auerbach, Soutine was a Jewish artist who had fled his home.

But where Soutine sees anguish, Auerbach finds what you could call serenity. Talking about postwar London, he said: “There was a curious feeling of liberty. Everybody who was living there had escaped death in some way. It was sexy in a way, this semi-destroyed city.”

More solo exhibitions followed and before long Francis Bacon, the talisman of a new generation of young radical artists who had emerged from the shadow of war, took the up-and-coming Auerbach under his wing. The pair dined and drank in Soho’s bohemian haunts, and together with Lucian Freud, R.B. Kitaj, and Maggi Hambling they formed the “School of London”, a movement that doggedly pursued forms of figurative painting at a time when the art world was dominated by abstraction.

But Auerbach’s closest connection at this time was with Leon Kossoff, another British Jewish artist and towering figure in 20th-century British art. They met as students at Saint Martin’s, and would go on to collaborate and model for each other for years to come.

Kossoff was also committed to a form of expressionism that revolved around urban landscapes and human figures. They influenced and borrowed from each other, resulting in an artistic dialogue between the two.

Auerbach’s Head of Leon Kossoff (1956-57) features in the Courtauld exhibition. Despite its stark monochrome colour, the portrait is rich in depth, texture and humanity. Like his landscapes, Auerbach revisits and revises sections meticulously, erasing and reworking them.

The remnants of the process are often still visible, granting the images a quietly captivating vitality. But in the late 1950s Auerbach was struggling. His 1958 self-portrait, also part of the Courtauld exhibition, hints at the artist’s personal struggle with something existential.

Auerbach’s self-portrait is one of few self-portraits that gazes out towards us. And while other sitters, friends and family are distinctly separate from their background, he appears almost ghost-like, as if the very light that surrounds him diminishes his presence. His right eye is smudged: only the left one stares uncompromisingly beneath a small ambiguous frown.

Although he downplays his Jewishness it’s difficult not to be reminded of his childhood trauma.

“I don’t feel I belong to a Jewish school, I don’t think there is such a thing,” he would tell one of his students. “Religion and ritual mean nothing to me.”

However, he has, on occasions, said that he would not disavow his Judaism as long as antisemitism exists.

But regardless of this, his images, especially the urban landscapes, retain a palpable sense of alienation. We see the city through a refugee’s eyes, the geography and psychology of the city swirling together into one.

But be careful not to overinterpret. To this day, Auerbach remains private, preferring not to offer commentary on his work.

“I don’t spend a lot of time looking at my paintings,” he coyly admitted to his biographer and muse Catherine Lampert. But there is no need to with his portraits. Their stark humanity speaks for itself.

However, he did liken his intention in painting to Robert Frost’s view of verse, as described in the poet’s essay The Figure a Poem Makes.

“He said, ‘I want the poem to be like ice on a stove — riding on its own melting,’” Auerbach said to Lampert. “Well, a great painting is like ice on a stove. It is a shape riding on its own, melting into matter and space; it never stops moving backwards and forwards.”

The Courtauld exhibition gathers 17 of his drawings with a selection of six paintings of the same sitters. Many of the portraits were made in Auerbach’s Mornington Crescent studio where, at 92, he still paints, captivated by his surrounding urban landscape, a haphazard mix of modern, Victorian, and Georgian architecture huddled together around the railway.