Just last week, the literary agent for UK author Patrick Ness was in Los Angeles discussing film rights to his celebrated Chaos Walking children’s book trilogy. “The first thing you find out when yer dog learns to talk is that dogs don’t got nothing much to say,” is the brilliant opening line of the first book The Knife Of Never Letting Go but Ness’ agent Michelle Kass tells me she has been deliberately holding off selling the rights, despite big Hollywood interest, until after Candlewick published the final book Monsters of Men in September. But Kass admits there are some problems with trying to turn Chaos Walking into the next Harry Potter. “First, the book takes place in a world where everybody can hear everybody else’s thoughts. Second, it has some very adult moments. But I think that the Chaos Walking books could be turned into an astounding film, and it’s not just a children’s film.” Her trip west couldn’t be better timed. It comes just as British Prime Minister David Cameron is exhorting the UK film industry to make more fantasy films based on bestselling British children’s authors, even going so far as to tell the House of Commons: “I think one of the keys to Warner’s success is the Harry Potter film franchise which they have been making. There is a great tip and key for filmmakers here. That is, we have got to make films people want to watch.”

Warner Bros in particular has been searching for another British kids fantasy franchise to replace Harry Potter now that it’s coming to an end. It needs to put something in its $161 million studio facility that will reopen in north London in mid-2012. The studio has just renewed its option on UK educator turned author Joseph Delaney’s children’s fantasy series, The Spook’s Apprentice, which has been in development since 2005 and is now called Seventh Son. Sergei Bodrov has been hired to direct, and Warner Bros and Legendary Pictures are co-financing. They’re co-producing with Lionel Wigram, executive producer of Harry Potter and the Deathly Hallows and a new children’s author himself, and Basil Iwanyk of Thunder Road (Clash Of The Titans). The book tells the story of a 13-year-old boy who is apprenticed to a forbidding wizard though I’m told the Warner Bros’ script now concentrates on the 2 teenage characters in the novel. Sounds like they’re making it more Harry Potter-ish.

Unlike the studios, the last serious attempt at making an indie British children’s franchise was 2006′s Stormbreaker, re-titled Alex Rider: Operation Stormbreaker for the U.S. market. Producer Marc Samuelson had high hopes this was a junior James Bond franchise. The film did great in Britain, grossing $13 million domestically and selling nearly 500,000 DVDs. But the film cratered in the States, grossing only $677,646 because The Weinstein Company released it on just 221 theatres, barely marketed it, and therefore scuttled any chance of a sequel.

The problem any indie producer has adapting a British children’s franchise is that preselling these films to the States isn’t cheap. Samuelson tells me that the minimum you need to spend is $15 million – working with children means short days, providing abundant action sequences — with another $20 million in P&A in the U.S. Plus, British kids’ books are often darker and edgier than their U.S. counterparts. But McDonalds, Burger King and the fast food rest won’t hawk the movie’s plastic action figurines if you rate more adult than a PG.

So what’sabout all the other great British children’s book franchises?

Artemis Fowl
It’s about a 12-year-old master criminal pursued by Irish leprechauns who want their fairy gold back. Described by author Eoin Colfer as “Die Hard with fairies”, the Artemis Fowl series has sold 20 million copies to date. Miramax optioned the books back in 2001 — there was a legal tussle over the rights when the Weinsteins left Miramax — and Disney keeps extending the option. Jim Sheridan (Get Rich Or Die Tryin’) wrote a script with Colfer but is no longer involved.

Skulduggery Pleasant
Irish playwright Derek Landry published the first novel in this award-winning 5-book franchise in 2007. Rooted in the horror, comedy, mystery, and fantasy genres, the story follows an undead wizard and detective Skulduggery Pleasant and his female partner as they fight a weapon of mass destruction. The first book was retitled Sceptre Of The Ancients for the 2009 paperback release in the U.S. and Canada. My information is that Warner Bros has let its option on the Skulduggery Pleasant books lapse although Derek Landy commented that there had been a director atached to the live action project and everyone was working on the script.

Cherub
English teachers complain that this children’s series seems to be the only thing British boys aged between 10 and 12 are reading. Sarah Radclyffe Productions (The Edge of Love) tells me it hopes to go into production next year once a new version of the script has been delivered. Christopher Smith (Triangle) will direct. Smith has talked about how he wants this to be much grittier and uglier than the Spy Kids premise suggests, saying it’s La Femme Nikita meets This Is England.

Mortal Engines
Peter Jackson has been developing an adaptation of Philip Reeve’s Mortal Engines quartet (known as The Hungry City Chronicles in the U.S.). Weta, Jackson’s VFX company in New Zealand, has been working on designs for the film. Reeves’s book series takes place in a steampunk post-apocalyptic future where cities perambulate around the world devouring each other for fuel. Given Jackson’s Hobbit commitment for 2 back-to-back films, the project’s status right now is unclear.

Noughts and Crosses
Malorie Blackman’s series of 5 children’s books are set in a racist Britain where people with black skin (Crosses) dominate the white minority (Noughts). It’s a Romeo and Juliet-type saga where a black teenage girl falls in love with a white boy. Given the Shakespearian theme, the Royal Shakespeare Company staged the first book, Noughts and Crosses, in 2008. Blackman’s agent The Agency tells me a film version of Noughts and Crosses was planned but that option has now lapsed.

Mortal Instruments
Not a British book, but being made by a European production company. German producer/distributor Constantin Film (3 Musketeers) is developing Cassandra Clare’s young adult urban fantasy trilogy Mortal Instruments with Unique Features and Sony Pictures’ Screen Gems. Jessica Postigo’s script is based on the first novel in the series City of Bones which follows a teenage girl who realises that she has special powers when she joins a teen gang in a modern-day New York infested with werewolves, witches and warlocks. Clare has written on her blog that she’d like to see Emma Stone as the teenage heroine.