Trapped in England during the war, the young John Craxton was one of the brightest hopes of British art when escaping to Greece in the spring of 1946.

He made his adopted home on an Aegean shore for the next 60 years. Crete in particular became the inspiration for sparkling colourist paintings and profound portraits produced even when he was far away and, for a decade of military rule, in exile.

To coincide with the Charmed Lives in Greece: Ghika, Craxton, Leigh Fermor exhibition at the British Museum, Craxton’s first major selling show for 25 years comprises unseen works from seven decades in his studio when he died in 2009.

Craxton kept his passport and a toehold in London – and was finally elected a Royal Academician in 1993. But on what some perceived as a permanent holiday in the sun, he was taken less and less seriously.

Indeed, during the middle decades of his long life he was best known – if noticed at all - for the glorious jackets to books by his friend Patrick Leigh Fermor.

But in private – and almost in secret – he was working and reworking the glittering images of Greek light, life and landscape which mirrored his own joyful existence.

Reluctant to sell his pictures, he preferred to buy works back. Now 50 previously unknown paintings and drawings from the Craxton estate are being offered by Osborne Samuel in the first of a series of posthumous exhibitions.

In life and in art John Craxton charted an independent path. He moved from dark, melancholic neo-Romanticism (though he hated that label) through semi-Cubism and on to an exhilarating vocabulary embracing ancient Greek myth, the topography and temperament of Arcadia and a love of Byzantine mosaics. Reinventing his technique with every picture, his artistic language became absolutely his own. At last he can be appreciated as a modern British – and Greek – master.