As Wallace and Gromit ride again in a new film and exhibition, Graeme Virtue pays tribute to the Plasticine national treasures

IN May 2004, a fire on an east London industrial estate destroyed dozens of stored artworks, including more than 100 owned by self-appointed modern art tsar Charles Saatchi. Conceptual pieces by Tracey Emin, Damien Hirst, Chris Ofili and the Chapman brothers were lost forever, yet many commentators adopted a near-gleeful tone at the bonfire of such vanities. "Didn't millions cheer as this rubbish' went up in flames?" asked one columnist in a middle-market newspaper.

Some 18 months later - on October 10, 2005 - a fire spread through a Grade-II listed building in Bristol. The blaze destroyed original drawings, wooden sets, paperwork, awards and other memorabilia accrued over almost 30 years by Aardman Animation, including materials from the first adventures of Wallace and Gromit, the company's most beloved ambassadors. This time, the tone of reporting was very different: the loss of Aardman's historical archive was perceived as a national tragedy.

"I was quite moved by how much news it made," explained Nick Park, the creator of Wallace and Gromit, the following year. "It sort of said, This is an important part of British film history.' I never knew that was how it was being valued. So that was quite nice."

It's easy to imagine that final phrase - "so that was quite nice" - coming from the mouth of optimistic crackpot Wallace (although it would probably take three or four days of painstaking stop-motion animation to achieve the effect). Nick Park's fingerprints are all over his wireframe-and-Plasticine creations, sometimes literally, and while Aardman has enjoyed other successes over the years - Tony Hart's dopey pal Morph, the ongoing Creature Comforts series of incongruous monologues, even the trombone-playing Lurpak man - none have been so warmly embraced by the British public as the bald, Wensleydale-loving inventor and his silent, faithful, often exasperated hound.

An insistent buzzword in contemporary TV production is "3G" (meaning "three generations"). It was inspired by the revivified Doctor Who, which succeeded in getting children, parents and pensioners all cowering behind the couch together. But 15 years before the Doctor redefined viewing demographics, Wallace and Gromit had effortlessly managed to appeal to everyone. Children were drawn to their squidgy features and slapstick humour, adults were relieved to briefly lower the carapace of cynicism needed to negotiate the modern world, and grandparents could warm themselves on the glow of 1950s nostalgia. In recent years, this generation-spanning fanbase has convened on the web, where one can download W&G colouring books to print out for the young 'uns or post a seasoned family recipe on the official forum. Now a popular family-centric Aardman exhibition featuring sets and models from Wallace And Gromit: The Curse Of The Were-Rabbit, which has been touring since 2006, is to visit Scotland this month for the first time.

Park first conceived the characters in 1982, while he was a student at the National Film And Television School, a campus 25 miles west of London. Originally, Wallace had a moustache as well as a flat cap (he was loosely based on Park's father, an "incurable tinkerer"). Rather more alarmingly, Gromit was a talking cat. The duo continued to evolve in Park's sketchbook, but even his early designs were enough to impress visiting lecturers Peter Lord and David Sproxton, the founders of Aardman Animation. They hired Park to work on their commercial projects - he had a hand in Peter Gabriel's putty-powered Sledgehammer video - while he continued to develop his own stop-motion short about an inventor and his dog.

It took six years for Park to complete his 23-minute film A Grand Day Out, mostly because breathing stop-motion life into his miniature clay golems was a one-man effort. The storyline seems a little far-fetched compared to later escapades - Wallace pilots a Jules Verne-esque home-made rocket to the moon in search of fresh cheese supplies - but the characters were beautifully rendered and winningly charming (it helped that Last Of The Summer Wine veteran Peter Sallis provided Wallace's northern burr). Just as impressive was the backdrop Park had painstakingly constructed: a fond-hearted vision of 1950s northern England soundtracked by colliery brass and augmented by Heath Robinson-style contraptions, like a Hovis advert crossed with Thunderbirds.

When it screened on Channel 4 on Christmas Eve in 1990, A Grand Day Out was an immediate hit. Though nominated for a Short Animated Film Oscar, it lost out to Creature Comforts, another Aardman production Park had originally dreamed up as a mere side-project. (Park now has four Oscars, three of which were earned by W&G.) Two further short films followed - The Wrong Trousers (1993) and A Close Shave (1995) - each expanding in ambition and budget, while remaining true to the spirit of the characters (northerners pride themselves on remaining grounded). It took a further decade for them to complete the journey to the big screen, but re-runs and runaway DVD sales kept Wallace, Gromit and the "Cracking toast!" catchphrase in the public consciousness.

Aardman had entered into partnership with Hollywood studio DreamWorks - the studio behind Shrek - to move into feature films. Their first, Chicken Run (2000), was a poultry effort featuring the voice of Mel Gibson; it took Park five years to guide the ambitious project to completion. It took another five to make Wallace And Gromit: The Curse Of The Were-Rabbit, which cast the enterprising duo as ethical pest controllers, sucking up dozens of cute bunnies with a turbo-boosted vacuum cleaner before facing an over-sized vegetable-chomping menace. Released in 2005, the film was highly praised and won another Oscar yet still performed badly at the US box office (it was a success in most other places). Despite nods to classic Universal horror movies, Park's vision was just too peculiarly British for the mass American audience. The relationship between Aardman and DreamWorks ended after one more film, Flushed Away, and while remaining unfailingly polite about the whole business, Park sounded a little relieved to leave Hollywood behind.

"It's nice to be out of that feature film pressure," he said. "I don't feel like I'm making a film for a kid in some suburb of America - and being told they're not going to understand a joke, or a northern saying."

This Christmas, the BBC will screen the first new Wallace and Gromit short since 1995. With Park leading a team of animators, artists and technicians, A Matter Of Loaf And Death was filmed in a mere 10 months (according to the official production blog, principal photography wrapped just last week). The duo have moved into the business of baking, installing a windmill on top of their terraced house and overseeing an automated production line of dough-kneading robot arms. There's a new lady in Wallace's life, Piella Bakewell (voiced by Sally Lindsay), but a murder mystery appears to threaten any chance of romance (former Miss Marple Geraldine McEwan is in it too). While the animation is still the same traditional stop-motion, A Matter Of Loaf And Death is being shot digitally (some fans, who have perhaps wiped their own hard drives by mistake, have expressed concern that the "film" could be accidentally deleted; a production assistant issued assurances that daily footage is being backed up and saved in two separate locations.) So after their sure-to-be-cracking return to the small screen, what does the future hold for Wallace and Gromit? Peter Sallis is 87, but still seems pretty sprightly on Last Of The Summer Wine (the 30th series screens next year). Park himself will turn 50 in December, but shows no sign of tiring of his most famous creations, despite the countless hours he must have spent hovering over them, incrementally moving an arm here, a tail there.

In spring 2009, a new £2m dedicated exhibition will open at London's Science Museum, which will recreate Wallace and Gromit's cosy, gadget-enhanced house (let's hope there's a smoke alarm). With interactive exhibits, creative activities and animated displays, it's sure to attract an army of would-be inventors, young and old.

There are also plans to erect a statue of Wallace and Gromit in Preston, Park's birthplace. And when they unveil that bronze of the inventor and his dog, their creator will have to resist the urge to lean over and adjust Wallace's thumbs-up sign or Gromit's arching brow. Like his father, Park is an incurable tinkerer.

Animated Adventures is at The Dick Institute, Kilmarnock from October 25 to January 31 2009. A Matter Of Loaf And Death will be shown on BBC One over Christmas