Picasso's lost disciple is back in the frame

The glaring omission from Tate Britain's current show on Picasso's impact on British artists is any representation of Keith Vaughan. More than any other British painter he embraced Picasso's return to classicism in the 1920s and 1930s. Also influenced by the other great Modernists, such as Matisse, De Stijl and above all Cézanne, he forged his own path of figurative art in the postwar period.

Once regarded as Britain's pre-eminent painter, he was overtaken by the brash artists of the Sixties, with their popular imagery and commercial profile. Vaughan, introverted, obsessive and seemingly backward looking, was left on the sidelines and committed suicide in 1977, aged 65.

A century after his birth, it is time to take a new look at this artist whose pre-occupation with the human figure and with sexual anxiety make him in many ways contemporary in feel. Pallant House Gallery in Chichester, near his birthplace in Selsey, offers a convincing retrospective. In just three rooms it covers most of his output, from his early sketches as a conscientious objector in the Second World War to his figures set in landscapes. It also includes the landscape pictures which, while lesser known, made up around half his output.

Through them we see him break out from his initial categorisation as a "Neo-Romantic", with Graham Sutherland, John Piper and Michael Ayrton, to follow his own style, from his exhilarating Assembly of Figures series in the 1950s and 1960s to his final, near-abstract landscapes.

"I believe," he said, "a painter has only one basic idea, which lasts him a lifetime. Mine is the human figure." He was right in the sense that most of the better artists have continuously searched to explore the possibilities and seek to break the boundaries of particular forms. But Vaughan did much more than simply combine the line of Picasso's nudes with the form and structure of Cézanne's Bathers. What makes his paintings so original, and so frequently compelling, is the tension he brings to his works – between man and nature, between flesh and form, colour and shape. For him art was a search for climax and release, as much sexual as intellectual, from the conflicts he felt in himself and exposed so frankly in his journals.

That he was homosexual had a lot to do with it. His figures are not openly erotic (although some of his private sketches were) but his concentration on the male nude and the extraordinary way in which he invests even the most abstract figure with a sense of flesh through his palette and brushstroke set him apart from his artistic heroes.

You can stand in the central room of the exhibition, devoted to his figurative art, and see how the muddy palette of the Cézanne-inspired Group of Bathers (1951) brightens up and pares down in the brilliant Assembly of Figures VII (1964); how he creates a moving, jostling mass out of paint patches in Crowd Assembling I (1967); how he reverts to blocks of colour in the Matisse-like Musicians at Marrakesh (1966-1970). It's the same in the next room, with landscapes, as the early idyllic views of woodmen and children in the countryside are succeeded by the more Cubist Village in Ireland (1954) and the later, semi-abstract Cenarth Farm (1962) and Mortimer's Farm (1971).

If Vaughan never reached the stature of the modern masters he so admired, he certainly took their lessons and made them his own.

Keith Vaughan: Romanticism to Abstraction, Pallant House Gallery, Chichester (01243 774557) to 10 June