Freud painted skin. Not the idea of skin, not an impression of skin, but the actual weight and texture and colour of a specific person's flesh at a specific moment. His portraits take months. The sitters come to his studio day after day, holding the same position, while he builds the paint surface in layers so thick that the canvas develops its own topography.

He was Sigmund Freud's grandson. The family left Berlin for London in 1933, when Lucian was ten. He became a British citizen in 1939. The biographical connection to psychoanalysis is unavoidable and he resisted it throughout his career, though his paintings of naked bodies on beds and sofas, viewed from above in harsh overhead light, invite exactly the clinical reading he rejected.

His early work is tight, linear, almost Pre-Raphaelite in its precision: the portrait of Francis Bacon from 1952, Girl with a White Dog, Hotel Bedroom. The shift came in the late 1950s when he switched from sable brushes to hog-hair, thickened the paint, and began working on a larger scale. The flesh became heavier, more present, more uncomfortable to look at.

He painted everyone the same way. The Queen sat for him (the result was controversial). His studio assistant and bookmaker 'Big Sue' Tilley posed naked on a sofa; the painting sold for GBP33.6 million. His whippets appear repeatedly. He insisted on working from life, never photographs, and never took commissions. People came to him.

He worked every day until a few weeks before his death in 2011, at eighty-eight. His last painting was unfinished on the easel.