WILLIAM Hanna didn't rate himself as much of an artist, but he helped create such popular cartoon characters as Tom and Jerry, Fred Flintstone, Yogi Bear, Top Cat, Scooby Doo and the Wacky Races gang.

The animation pioneer, who has died aged 90, and partner Joseph Barbera collaborated for nearly 60 years.

With their studio producing more than 3,000 half-hour cartoons, it's reckoned that every hour of the day, somewhere in the world, people are watching a Hanna-Barbera production.

The pair first teamed up shortly after Hanna went to work at MGM. He'd originally left college to work as a construction engineer but lost his job in the Depression. He found work with the company that created Looney Tunes and Merrie Melodies cartoon series, where he worked in the story department, and as a lyricist and a composer. Then came the move to MGM.

Hanna admitted: "I was never a good artist", but said that Barbera "has the ability to capture mood and expression in a quick sketch better than anyone I've ever known".

Their first pairing of a cat and mouse was in the short Puss Gets The Boot. Audiences liked it and an Oscar nomination followed, so MGM let them develop the theme. The result was the Tom and Jerry cartoons which won seven Academy Awards, more than any other series with the same characters.

They broke new ground by mixing the cartoon cat and mouse with live action stars Gene Kelly in Anchors Aweigh and Esther Williams in Dangerous When Wet.

The team's switch to TV was unplanned. The move was forced on them after MGM folded its animation department in 1957. Hanna-Barbera Productions was born, using "limited animation" technique to cope with the small screen's lower budgets. The accent was more on verbal wit rather than the highly detailed, and highly expensive, action of the theatrical cartoon.

Ruff And Ready was Hanna-Barbera's first TV series, followed by a series of creations that proved as popular with adults as children. The Flintstones was the world's first animated half-hour sit-com and remained in US-TV primetime for six years. Fred's Yabba Dabba Doo catchphrase echoed around the world.

Yogi Bear, Top Cat, Wacky Races and Quick Draw McGraw were among other Hanna-Barbera creations. So was Huckleberry Hound And Friends, which won the first Emmy Award given to an animated series. The Jetsons, which debuted in 1962, was the futuristic mirror image of The Flintstones.

Hanna and Barbera's strengths melded perfectly, according to critic Leonard Maltin, in his book Of Mice And Magic: A History Of American Animated Cartoons. Hanna brought cuteness, warmth and a keen sense of timing, while Barbera supplied the comic gags and skilled drawing.

Hanna-Barbera received eight Emmys, including the Governors Award of the Academy of Television Arts and Sciences presented in 1988. The company was sold to Warner Bros in 1996 but Hanna remained involved in its work until shortly before his death.