One, two, three let’s pollute the sea. Four, five, six let’s do our tricks. ” With a flick of long straggly hair, a hitching up of skirts and a rolling of trouser legs, work on the trail of destruction began in earnest.

A cigarette butt here, a mound of paper there; half-eaten food and crumpled-up containers were cast on to the beach without a care. Greasy oil slicks oozed into sight, immobilising seagulls and fish in their haste to join the dirtiest party St Hilda’s RC primary had seen.

Thankfully, this was only a story, designed to show the pupils that the north Yorkshire coast needed looking after. Puppets made out of beer cans and operated by the children drove the message home as Mary Walker, puppeteer and storyteller, stirred up anarchy in what, until her visit, had been a quiet school in Whitby, North Yorkshire.

The North Yorkshire Moors National Park education department has commissioned her to use her puppets, stories, songs and poems to “raise awareness in children and teachers that the Heritage Coast is a special place that needs looking after, and that each of us can do our part to help take care of it,” explains Sandra Spashett, the national park’s education officer.

“We do not want the children to be political. We want them to understand - to quote David Attenborough - that conservation is about keeping the balance between our needs, and the needs of our fellow earth-dwellers.”

Mary Walker’s project, Turning the Tide, is an interactive live show designed for primary schools which can be altered to accommodate the pupils’ particular needs: a litter problem, for example.

“The audience are the participants in the story,” said Mary Walker. “They make up the answers to my questions depending on their attitudes towards conservation. But, ultimately, the aim is to get them to think about the issues of development versus conservation and at the end hypothetical decisions will be discussed.”

Turning the Tide builds on participation theatre work which staff at NYMNP had been doing with adults to get the same messages across, until they decided that they were preaching to the converted. The puppet project seemed to be a way to relate the importance of conservation to the local coastline, while involving children Mary Walker’s brief was to motivate pupils to explore the issues creatively. Having worked as an educational puppeteer for 15 years, she wanted to stage a live discussion rather than put on a puppet show. In an hour of frenzied activity, the 45 children produced a variety of puppets to represent the animals that inhabit the cliffs, moorlands and seas. The mermaids were all set to distract the odd ship or two. There were badgers (resembling big furry microphones) and what looked like a new species of greater hairy North Yorkshire fish.

In the darkened dining hall, set up to represent various types of coastal habitats, with holes for the animals and grottoes for shadow puppets, the children put on an impromptu 20-minute performance before their invited audience - five and six-year-old “developers” who had heard that a desirable coastal plot was for sale. One of them wanted to build a new holiday park on the cliff with a boating marina below.

In her guise as Madame Silkie the seal, Mary Walker called on the animals to air their grievances against humans. The rabbits told of the shooting problems they were having and their fear of the hot ovens. The bees complained they couldn’t make honey any more, and the mermaids, looking alluring in their sequinned bras, said they were too sad to lure. George the hard-hearted builder wanted to imprison them in a Jurassic Park-style attraction.

Madame Silkie also introduced some very unpleasant characters that pose a direct threat to the environment - oil slicks, litter, nasty chemicals and sewage. The puppeteers tried to persuade their audience that the damage the developments would cause to the habitat would outweigh the commercial advantages (or would it?).

But as Mary Walker says, “The questions are not black or white, nor are the children expected to only take the animals’ part against the rapacious humans. The story does not have a happy or sad ending. It is discussed and decided through the performance, and the pupils are encouraged to come up with solutions and options.”

Mary Walker, 11 The Village, Holme, Holmfirth, West Yorkshire HD7 1QG. Tel 01484 685577. Sandra Spashett, education officer, NYMNP, The Moors Centre, Danby, Whitby, North Yorkshire. Tel 01287 660540