Sometime today, Harold and Kate Shapinsky -- their few possessions in storage -- will S turn over the keys to their fifth-floor walkup above a Japanese restaurant and leave for London. Which makes sense. Here, Harold Shapinsky is a painter without a gallery or a reputation, an Abstract Expressionist whose style has gone quite out of fashion, a lifelong artist who has reached 60 without ever having a studio, a major New York exhibit, critical or popular recognition.

In London, however, Harold Shapinsky is a sensation.

A show at the Mayor Gallery last month drew unheard-of crowds while collectors bought all 22 of Shapinsky's oils at an average price of $25,000. The prestigious Tate Gallery bought one of the untitled works, Shapinsky's first museum sale. The artist, the subject of a British television film and of intense press interest, became so well-known that passers-by congratulated him on the street. Plans are afoot for exhibits in Cologne in September and, tentatively, in New York next year.

After 40 years of dignified obscurity, Shapinsky is on the verge of art world renown, a home with a garden, room to work on more than one painting at a time. He is entitled to sound ebullient, to feel vindicated, to go on shopping sprees or even ride in taxicabs, but he is much too quiet and level-headed. The most he can say about the whole extraordinary turn of events is that it is "marvelous." If pressed, he'll say it's "very marvelous."

If none of this had happened, Shapinsky says, sitting at the kitchen table of his tiny, three-room apartment on the upper East Side, "I'd still paint. For the love of it." Thin and gaunt-faced beneath his gray beard, wearing plain jeans and a pale cotton shirt, he lights and relights his pipe.

"But it's nice to know," puts in Kate Shapinsky, piecing a quilt in the next room, "that I won't have to climb all these stairs."

Shapinsky, whom his wife calls "Hesh," says very calmly that he was never troubled by the prospect of growing old without a pension or a nest egg.

"Well, it was on my mind," says Kate, a dancer turned craftswoman who met her future husband at a New Year's Eve party as 1947 became 1948. "I'd walk along the street and see women without homes."

Their particular fairy tale (apart from the happy ending of being married for almost 40 years and still holding hands as they walk down East 70th Street) began last year in Chicago. Their son David, a graduate student at the University of Chicago, was showing slides of his father's work to the guests at a party, among whom was an English teacher from a college in Bangalore, India. Akumal Ramachander fell in love with the abstract paintings and resolved to champion them. (He said later that Shapinsky's work recalled the flocks of butterflies he had seen in a field outside Calcutta as a child.) David Shapinsky called to tell his parents that Ramachander thought the work deserved to be seen. "I thought it was marvelous," Shapinsky says.

Ramachander had the paintings photographed at his expense and began his assault on the art establishment, but his calls to about 30 Manhattan galleries did not locate one willing even to look at the slides. He got luckier in London, where he appeared without an appointment in the lobby of the Tate Gallery and buttonholed its curator of modern art, Ronald Alley. Alley took a look at the slides and, he later recalled in the catalogue of the Mayor Gallery exhibit, "I was amazed that a real Abstract Expressionist painter of such quality should be unknown . . ." Alley sent Ramachander to gallery director James Mayor, who agreed last December to give Shapinsky his first one-man show, slated to open on Shapinsky's 60th birthday in May. Shapinsky thought this, too, was "marvelous."

One might say the same of several related developments: Ramachander told his friend, the novelist Salman Rushdie, of his discovery; Rushdie told his friend Tariq Ali, known in London as a yippielike political activist but also a filmmaker. All this activity bore fruit when the Shapinskys made their first-ever journey to Europe in May. As the Mayor Gallery show opened, Ali's hour-long documentary (titled, in honor of Shapinsky and Ramachander, "The Painter and the Pest") aired on independent television and Rushdie's article about the whole process appeared in The Observer. The Mayor Gallery, which normally attracted 20 to 30 visitors a day, was drawing 50 an hour.

"The Gallery's never been fuller," says James Mayor, now Shapinsky's agent, crediting "the excitement of the painting, and the feeling of discovering something. It's such a beautiful story. The man painted solidly for 40 years and then suddenly everyone takes notice."

"As long as the work is appreciated," is Shapinsky's measured response. "And there was enormous appreciation in London. Almost everyone liked them very much and came over to us and said nice things. It was a very good feeling." This is as triumphant-sounding as he gets.

The man whose work the throngs were seeing, and buying, is Brooklyn-born and had little formal art training. He briefly attended the Art Students League, but "my teachers said I should go home and paint. I was always moving towards abstraction."

Other New York painters were also moving toward abstraction in the 1940s, of course. "In 1946 or so I saw an exhibit by Abstract Expressionist Arshile Gorky and felt this immediate connection. It was like meeting an old friend. A year or so later I met some of the Waldorf Cafeteria painters" -- among them Willem de Kooning. "It was open all night, painters came after work," is the way Shapinsky remembers the place, sounding not at all nostalgic. "We could talk, have coffee, sometimes draw on napkins."

During this brief flirtation with the New York art world, Shapinsky studied with Robert Motherwell and Mark Rothko at The Subjects of the Artist school on Eighth Street. "Motherwell liked my work," Shapinsky says. "I was very much encouraged." One of his paintings was included in a New Talent Show in 1950. "There was a lot of interest; it was reviewed by The Times and Art News."

Yet somehow, though Shapinsky never stopped painting and drawing, the interest here and encouragement there never fused into a marketable career. With only occasional group shows through the '50s and '60s, New York soon forgot there was an Abstract Expressionist named Harold Shapinsky. He insists it didn't matter.

"A lot of it had to do with the politics involved," he says with quiet distaste. "You have to do a lot of socializing, go to bars and parties . . ."

"Which we did a certain amount of," interjects Kate, sorting her quilting scraps.

"For a while," he says. "It really wasn't that terribly interesting. To get into galleries you had to be very friendly with artists. I wasn't that involved with many of the artists. You had to constantly bring photos or slides to the dealers and I didn't do that. I just avoided it. I wasn't that concerned with the commercial aspect of it. I loved painting. That's what I was concerned with."

Denied compensation for his passion, Harold was sometimes a house painter, sometimes a dealer in antiquarian books. Kate sold her quilted garments and wall hangings, sometimes to trendy Bendel's. The Shapinskys formed a children's arts workshop in Queens, he teaching art, she concentrating on dance. They raised David on the Lower East Side, where Harold was head of the block association, involved in planting trees and forming safety patrols and improving the public schools. (They talk like unrepentant liberals all over the city of how they used to support congressman Ed Koch and how Koch as mayor has betrayed them. "He's only for the rich," says Shapinsky, who doesn't sound acutely aware that, having just sold roughly half a million dollars' worth of paintings, he's verging on rich himself.) When, on occasion, community affairs intruded into time he wanted to spend painting, he drew.

"We always managed," he says mildly.

"I think we lived better than most," says Kate.

"It's an attitude."

"Hesh is an excellent shopper."

"We always ate well. We weren't concerned with things."

Still, there were sacrifices. Shapinsky painted on thick paper, partly because he liked the feel but partly because canvas was too expensive. In any case, there was no room to store canvases in the family's various small apartments. When James Mayor visited his new exhibitor to select works for the show, he found decades of paintings layered in portfolios or rolled up and standing in cardboard boxes in Shapinsky's front room, leaving a billiard-table-sized space in which the painter could actually paint. To save space he sometimes tacked his paper on the wall instead of using an easel. He still keeps his paints and palette (and a small radio -- Shapinsky listens to classical music or jazz while he works) on a wooden table he bought at a secondhand store. Since Kate uses the rear of the three rooms for her quilting and knitting, and the middle room is the cramped kitchen, the couple sleep on a futon they unroll at night.

Their tight quarters also account for Shapinsky's paintings being small, usually less than two feet wide. "Even when the paintings are this big," he says holding his hands slightly apart, "they feel like Miro's. They fill a wall."

Like Miro'? Critic John Russell Taylor wrote in The Times of London that Shapinsky is "an extremely good and original Abstract Expressionist" whose forms "have an extraordinary interior energy" and whose colors show "exquisite subtle harmonies."

But the Guardian's Waldemar Januszczak was less flattering in a piece headlined "The Art of Hype." Januszczak complained about the film and press blitz and concluded that the exhibit was "exactly what we would expect from a minor Abstract Expressionist who has worked long and hard in timid isolation: unoriginal, nostalgic, small, intense, occasionally charming, sometimes beautiful. It is good but not great art."

Januszczak told reporter Nigel Lewis, who covered the Shapinsky saga for the Canadian Broadcasting Corp., that he had never felt under such pressure to notice an artist. "He's not an original painter . . . he's a second-generation man," the critic said in a radio interview, suggesting that the best-informed assessment of Shapinsky's work would come from New York's Museum of Modern Art, "the people who really know what American Abstract Expressionism is."

Those people are unimpressed. MOMA director of painting and sculpture William Rubin happened to be in London during Shapinsky's show. "I went in because there was a certain flurry of notoriety," Rubin says. "To be kind, the man is a serious but wholly unoriginal artist. The pictures were imitative of the 1948 to 1950 work of Willem de Kooning." Rubin says MOMA will neither acquire nor exhibit Shapinsky art and adds, "I don't think any serious dealer in New York would dream of exhibiting it."

Thus Salman Rushdie may have overstated the case when he wrote that "the history of Abstract Expressionist painting will have to be rewritten" to include Shapinsky's name "in the same breath" as Jackson Pollock's and de Kooning's. But whatever art historians eventually make of Shapinsky, Harold and Kate's lives are going to grow easier. It couldn't happen to a nicer guy.

"Well," he says, "it's marvelous." The Shapinskys had looked before for a home outside the city, where even their modest apartment rents for $700, consuming a major chunk of their income. "But we discovered you had to drive to get around, and neither of us drives. But we're very interested in living somewhere there's a garden, where we could grow things."

"We're going to try it out for size," Kate says of London. "We met an awful lot of people who were awfully nice. We even met someone who kept bees, right in the city," she adds, charmed at the notion.

"You don't have all these huge skyscrapers," explains Harold, whose view from the front room where he paints is of the facing windows of a white high-rise across the street. "It's just very difficult for artists to live here, even if you're making some money. Hundreds of thousands of dollars for lofts in SoHo."

London, by contrast, "has a marvelous quality; it's friendly, beautiful, rents are cheaper, restaurants and clothes are less expensive. We may buy a house," he smiles, quietly. "It'll be marvelous to have enough room to spread out, work on some large things, work on several things at once."

He says the best thing about the whole state of affairs is having his work seen. Kate says she'll stick with her fabric artworks. The Shapinskys would love to talk more, but they must leave for a celebratory lunch with a friend. Of course, they will walk the 20 or so blocks to their friend's midtown office. "Here, my love," says Kate, presenting Hesh with a plastic bag of garbage to dispose of on the way out. Then, arms intertwined, they set out along East 70th Street.