Catherine Milner finds much to commend the early draughtsmanship of one of Britain's best-known living artists.

David Hockney is the ultimate poster boy. His pictures of Californian skies and turquoise pools adorn the walls of student cafes, station waiting rooms and doctor’s surgeries almost as often as Monet’s waterlilies. For those who find his works now rather hackneyed, this exhibition in the sleek new Mayfair premises of the Offer Waterman gallery is a salutary reminder of why he became so famous in the first place.

Although best known for his paintings and hailed as a great colourist, it is in his simple line drawings that Mr Hockney’s peerless judgment of line and form is revealed. On show are examples from his very earliest work, from the lumpen-headed, Dubuffet-inspired figures he did immediately after leaving the Royal College of Art in 1962 to drawings of life in California, where he was lured by the surf, sun and promise of ‘beautiful boys’.

‘In 1964, they [the boys] used to look fantastic,’ he has said. ‘I mean, there was a very Californian look, quite distinct-ive. Nobody looked like that anywhere else. It was marvellous. It’s a warm climate. People don’t wear that many clothes.’

Quite apart from not wearing clothes, many of the subjects in this exhibition are not awake either. Pictured in the bleak, Dralon-furnished bedrooms of the hotels Mr Hockney frequented on his travels around the USA, his friends and lovers are seen in varying degrees of slumber. Particularly tender is his portrait of the writer Jeff Goodman, which shows him sleeping in a tight cocoon of sheets with his head poking out from the top like the handle of a spindle of cotton.

So, too, is the watercolour sketch (later turned into a painting) of one of the artist’s early big loves, Peter Schlesinger, seen fast asleep wearing just a T-shirt and tennis socks. There is another, a sketch of his art dealer John Kasmin conked out on the grass, which, through the perfectly judged lines of ribcage and nose, creates an image so immediate, it looks as if he is breathing.

David Hockney, Early Drawings at Offer Waterman

The Luxor Hotel (1978): Hockney still never travels anywhere without a sketchbook (or an iPad).

In most of the drawings, Mr Hockney focuses on the head and, in particular, the hair, leaving the rest of the figure to a few cursory lines. The sunburnt face of his boyfriend, Gregory Evans, pictured wearing his golf cap, is framed by the kind of laboriously worked frizz you see in Rembrandt’s portraits.

In another, Mr Hockney relishes the tousled Byronic curls belonging to one of Mayfair’s most infamous and rude restaurateurs, Peter Langan. There are many pictures in crayon that the artist probably worked on far harder, but generally they lack the fluency of his monochrome pieces and are not as good.

Mr Hockney’s whole life can be documented through his sketches there are literally thousands in his archive in California. ‘When David Hockney moved into his London flat in Powis Terrace, Notting Hill, in 1963, one of the first things he did was to paint in large capital letters a sign at the end of his bed which read “GET UP AND WORK IMMEDIATELY”,’ remembers his friend and biographer Christopher Sykes.

David Hockney, Early Drawings at Offer Waterman

For sleepy Kas (1967): Often Hockney’s firends, such as Kasmin, would find themselves the subject of close observation.

‘This says everything about him,’ continues Mr Sykes. ‘He is driven by a work ethic which started as soon as he could hold a pencil, when he drew on the linoleum floor in the kitchen of his parent’s home in Bradford and, paper being scarce at the time, scribbled all over the white paper margins round his brother’s comics.’ The artist is always doodling away at meals and buys jackets with extra big pockets to fit his sketch book, iPad or whatever he is using to draw on.

The selection shown here, part loaned and partly for sale, is particularly well curated. Unfortunately, the Hockney estate has permitted only two of the pen drawings to be illustrated, so, to appreciate the full panoply of the 55 works, you will have to visit the exhibition. ‘In my opinion, Hockney is one of the greatest draughtsmen in the world the power of his drawings is quite incredible,’ Mr Sykes says. Having already seen the show, I find it hard to disagree.

‘David Hockney, Early Drawings’ is at Offer Waterman, 17, St George Street, London W1, fromSeptember 25 to October 23 (020–7042 3233; www.waterman.co.uk) and also at the Paul Kasmin Gallery in New York, November 3 to December 1 (00 1 212 563 4474; www.paulkasmingallery.com)