He might be a tyrant, but The Highway Rat is set to spread much festive joy this Christmas as he embarks on an animated adventure perfect for the whole family. Best-selling children’s writer Julia Donaldson tells why, despite her character’s wrongdoings, his sweet tooth makes him impossible to resist.

Julia Donaldson has turned a blind eye to her longstanding family tradition of no TV on Christmas Day – for half an hour, at least.

For since 2009, the clever team at the Oscar-nominated Magic Light Pictures has been transforming the writer’s best-selling children’s reads into animated specials for the BBC, starting with the beloved Gruffalo, through to The Gruffalo’s Child, Room On The Broom and the tear-jerking Stick Man.

And this holiday season is no different as the broadcaster is to serve up its fifth helping of page-to-screen family fun with The Highway Rat.

Published in 2011, the hit tale – written by Julia and illustrated by Axel Scheffler – follows a swashbuckling rodent (complete with mask and cape) who terrorises animals along the highway, stealing their food at every opportunity. Clover from a rabbit, nuts from a squirrel and a leaf from some ants – he even steals his own horse’s hay, bellowing: "Give me your buns and your biscuits! Give me your chocolate eclairs! For I am the Rat of the highway, and the Rat Thief never shares!"

But will he get his comeuppance?

"I just wanted to do another book about a baddie, because I hadn’t done one for a while," Julia, 69, says of her greedy protagonist who, in this adaptation, is voiced by former Doctor Who David Tennant.

"I was going through the list of possible baddies and I thought, ‘I’ve done a dragon, I’ve done a Gruffalo. Highway Rat would be a good baddie!’. And I remembered the poem I’d loved when I was at school, The Highwayman by Alfred Noyes, which has that rhythm of riding, riding, riding."

Joining David is a stellar cast of British acting talent including Nina Sosanya and Tom Hollander, voicing the duck and the squirrel; Frances de le Tour voicing the rabbit, and Rob Brydon narrating.

But there could only be one rogue, Julia insists with a chuckle: "I went through bad animals; it’s usually a wolf or a fox and I thought ‘I can’t quite see them on the horse!’ And then I thought ‘Maybe a rat?’ It’s awful stereotyping. I feel very sorry for rats."

Despite his wicked ways, however, Julia is the first to admit she feels affection for the menace. Her basis: his penchant for sweet stuff.

"I must have quite early on thought that he could love sweets and chocolate, so that immediately gave me a soft spot for him," she explains. "So although he is one of my very worst baddies – he is a tyrant – I’m a bit mixed up about the Highway Rat. On the one hand, I get very serious and say it’s a story about tyranny and these animals are tyrannised by this horrible dictator.

"And I do feel it has a bit of relevance in the world today, that there are people seeking their freedom – but the chocolate and sweets ‘thing’ makes me sneakily fond of him."

Would the London-born laureate – who also counts an OBE among her accreditations – label The Highway Rat a firm favourite among the 20-strong Julia-Axel portfolio? "It’s definitely one of my favourites because of that poem – the Alfred Noyes poem – and because I managed to capture that rhythm," she says. "So I feel it’s one of my more patterned, structured texts. Plus, I like that ambivalence of the villain."

The Highway Rat is on BBC1 on Christmas Day at 4.45pm

DREAM STORY TEAM

Since Julia Donaldson and Axel Scheffler’s first book together, A Squash And A Squeeze, was published in 1993, the pair have gone on to become the most popular picture book collaborators in the business.

And apart from a few exceptions – the captivating Gruffalo and Zog – many of their stories remain unique one-offs, as opposed to churning out sequels to successful works.

"I suppose a lot of the books, for me, they’re sort of fables. They’re stories rather than episodes in someone’s life,” Julia muses, brushing off talk of a Highway Rat follow-up.

"I just find it easier, more satisfying, to start afresh with a new cast of characters."

So what can we expect to see next from the dynamic duo?

"The latest book, The Ugly Five, has just come out, so we’re slightly resting on our laurels," she answers, candidly.

"And at the moment, I’m trying to write something, but whether or not I’ll succeed ..." she trails off.

"The plan is, the official plan is, that we have gap year in 2018 and hopefully we’ll do another book in 2019."