Where do you see paintings by Ruskin Spear (1911–90)? In the salerooms mostly, because his work in public collections is rarely on display. Until the National Portrait Gallery closed for redevelopment it was, however, possible to study Spear’s splendid portrait of ‘Citizen James’ (Sid James) peering from a black and white TV screen, and his oil sketch of Harold Wilson wreathed in pipe smoke, the epitome of political cunning. Both were strikingly more convincing than their companion array of anodyne commissioned images.

Like his beloved Sickert, Spear painted commissioned portraits but also took to making enigmatic ‘unofficial’ portraits based on press photographs — or, in the case of Sid James, a snap off the telly. The first of these spirited commentaries on the great and the not-so-good was a large unflattering painting of Churchill speechifying at the microphone. This was greeted with hostility when hung at the Royal Academy Summer Exhibition in 1957. It is now lost, possibly destroyed, though a smaller version hangs in the Beaverbrook Art Gallery in Canada. This was followed by Spear’s swagger portrait of Princess Margaret en route to Balmoral. Over seven feet in height, ‘Catching the Night Train’ hung briefly at the Summer Exhibition of 1959 before being taken down because the picture ‘could be construed as satirical’. True enough — but it remains the best modern picture of a royal aside from Sickert’s nervy Edward VIII in his Welsh Guards uniform. Sadly, the Princess Margaret painting is in a private collection, as is Spear’s extraordinary attacking portrait of Enoch Powell entitled ‘Study Against a Black Background’, painted shortly after his inflammatory ‘rivers of blood’ speech.

Spear could paint lyrical townscapes when he chose. His ‘Snow Scene’ of 1946 , a view up Rivercourt Road in Hammersmith, the punctum the Methodist church spire on the corner of King Street, is in Tate Britain (though not at present on display). Hammersmith Bridge, with its massive stone piles, ironwork and suspension cables, became Spear’s Mont Saint-Victoire, and he painted the River Thames in all seasons, in darkness and light. The pubs of Hammersmith inspired some of his finest pictures, sacral records of those dark interiors with their iconography of polished brass work, frosted and mirror glass, vases of bounteous flowers on the counter, a canary in a cage. It was a world unto itself, utterly different from the bohemian drinking places of Soho and Fitzrovia. An unfamiliar face would not be welcome and middle-class visitors could quickly feel out of their depth. But the denizens of the public bar were Spear’s friends — figures such as Ernest Marsh with his one wonky eye, painted by Spear in a proto-pop spirit, again and again.

The London Borough of Hammersmith was Spear’s terroir. It was where he was born, where he contracted polio aged two, where he grew up, adored by his mother and four older sisters, and where he learnt skills from his coach-painter father. He attended the local Brook Green (PD) School, sent there by the London County Council. In the tough parlance of the period PD stood for Physically Defective, but although Ruskin had a gammy polio leg, he grew up tall and burly and, in his youth, handsome. An LCC scholarship took him on to Hammersmith School of Art and to the Royal College of Art. A working-class artist who became a Royal Academician, he was a brilliant painterly technician and as the tutor of, inter alia, Frank Auerbach, Peter Blake, Sandra Blow and David Hockney, he was someone to react against, stomping round the painting department of the Royal College until his retirement in 1975.

Spear’s brand of socially committed art — which satirised pools winners, politicians and fellow artists from Henry Moore to Barnett Newman — alarmed British critics and quite soon the word ‘vulgar’ was being deployed. After all, here was a painter whose art was discussed in the Times and the Studio but also in the Daily Mail and, most playfully of all, in the People and the News of the World. And that, for our cultural gatekeepers, would prove to be a problem. All of which serves to remind us that much 20th-century British advanced art is very tasteful and short on humour. And short on politics too. After all, Spear was a painter with his very own MI6 file, earned for his ‘peacenik’ activities during the Cold War.

A word about who collects or collected Spear. When I was writing my book about the artist, finding his work was not easy. But I came across some interesting characters who had bought up Spears — like the former Labour premier of Western Australia the title of whose autobiography, A Tumultuous Life, was, for once, genuinely accurate. In the 1950s curators of public collections in the provinces and in the Antipodes (where some of his early best work is to be found) acquired Spears partly because they were homesick for the people and streets of London. John Hewitt, left-wing Ulster poet and director of the Herbert Art Gallery in Coventry, bought Spear’s ‘London Whelk Woman’ in 1961 because he wanted art that addressed everyday life. No one painted flower-sellers, barbers, women ironing, waiters, bar ladies and men and women nursing a drink in a back bar more tenderly than Spear. Finally, I came to believe that liking Spear meant that you were OK. It was a litmus test — indicating kindness, humanity and generosity of spirit. Recently we have seen a stream of major shows foregrounding serious British figurative art, invariably focused on Francis Bacon and Lucian Freud along with pick-and-mix Michael Andrews, Auerbach, William Coldstream and Lawrence Gowing. No Ruskin Spear. That is how we seem to like it.