Regularly stroking his wispy silver beard, and supported around a central London gallery by a walking cane, the man dubbed the "godfather of Pop art" still struggles to come to terms with his place in the world of contemporary culture.

"It's a cross I bear," he said of the fact that his art is not taken as seriously as that of some contemporaries.

"Perhaps it's surprising that at my kind of age and with my infirmities I'm still cheerful," he told Reuters at the Waddington Custot Galleries where his latest show, "Rock, Paper, Scissors" has just opened.

Surrounding him are works ranging from some of his earliest watercolours executed in 1948 when he was 16 to "The Family", a sculpture he completed just a few days ago.

What is striking is just how lively they are - plastic figures of Snow White and 30 dwarves crowd outside a model of a Swiss chalet in one humorous work, and the six-foot-long "A Parade for Saul Steinberg" is a model bursting with color and references to popular culture.

Blake concedes that he is often left having to defend his work in a world where "serious" art is cherished above all.

"Painters all have a different reason to paint - it could be politics, it could be angst, it could be anger. My reason to paint is to make magic and to make cheerful things."

He has compared himself to contemporaries like Frank Auerbach, 81, whose dark oil paintings are increasingly sought after by collectors.

"Compared to that I am light, I have to accept that," Blake said, adding that he is a great admirer of Auerbach. "It is the reason I am quite often aesthetically undervalued."

TELLING OFF THE TATE

The art market clearly ranks his peers above Blake, including Auerbach and David Hockney, whose "Beverly Hills Housewife" fetched $7.9 million at auction in 2009.

But more of a bugbear is being overlooked by Tate Modern, the most important British gallery for modern and contemporary art which, ironically, gave a major retrospective this year to a much younger artist whom Blake helped nurture - Damien Hirst.

After uttering a few choice words in what he himself called a "rant" to a newspaper against the influential Tate director Nicholas Serota, he sought to strike a more conciliatory tone.

"Oddly enough Serota came in earlier to see the show," Blake recalled. "I said, 'Look it's not personal. You're the director of the Tate ... and if I don't fit into your scheme I'm not that bitter about it. It's a fact. I don't hate you.

"I think he was slightly embarrassed because I have been quite voluble about it. He accepted it."

What Serota would have seen at the exhibition was an artist still bursting with ideas in a phase of life he describes as an "encore" to the main acts of his career.

Blake named the show after the children's game "Rock, Paper, Scissors", and the childlike runs throughout.

"Rock" represents sculptures, some of which are occupied by superheroes, Boy Scouts, toy soldiers and knights alongside the more sobre "Army" consisting of human figures made up of wooden blocks topped by bowling balls for heads.

"Paper" covers works on paper that include Blake's portrait of Queen Elizabeth commissioned by the Radio Times for the cover of its 2012 Diamond Jubilee souvenir issue.

"Scissors" stands for collage, and the works range from abstract 1950s creations to a series of scenes of prominent London landmarks like Westminster Abbey and Piccadilly Circus populated by comic characters, animals, skeletons or horses.

Asked how his recent work compared to earlier "acts", he replied: "It's not a development, it's a leaping about.

"I describe my working methods as being like a big oak tree and the trunk is and has always been that I am a figurative painter of a certain kind of realist style - I was when I was 16 and I still am. But the branches of the tree are these excursions into other art."

MUSIC'S MOST FAMOUS SLEEVE

Blake was producing art by 1945, aged just 13, and in the 1950s and "swinging 60s" emerged as one of the frontrunners of pop art which drew on popular culture and advertising to subvert the traditions of mainstream art.

He is best known for designing the album sleeve for the 1967 Beatles album "Sgt. Pepper's Lonely Hearts Club Band", featuring a collage of famous figures behind the band members dressed in bright military-style regalia.

It is one topic Blake is keen to avoid.

"Best if you don't," he replied with a grin, when asked if he was willing to talk about a design for which he was paid a reported 200 pounds. "I'd much rather talk about this work."

That album has led to a lifelong association with British pop music, including designing sleeves for charity single "Do They Know It's Christmas?" in 1984 and Madness's latest album as well as the BRIT Award statuettes earlier this year.

Blake, it is clear, is still going strong, but only recently the outlook was far less rosy.

"All last year I wasn't very well, and I was talking often about the fact that I was working on this show and I hoped I would live long enough to go to it," he said.

"The question is there in the background, of mortality, but I've cheered up a bit and I'm not so unwell and I'm not forecasting my own death yet."

(Reporting by Mike Collett-White, editing by Paul Casciato)

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