BBC Films have decided to amend the name of Swallows And Amazons character Titty Walker.

The nine-year-old character – who will be portrayed by Teddie-Rose Malleson-Allen, the half-sister of singer Lily Allen – will now be renamed Tatty in the new big-screen adaptation of Arthur Ransome’s classic novel, after the filmmakers thought the original name would provoke sniggers.

Lily Allen and Teddie-RoseLily Allen and Teddie-Rose (Johnny Green/PA)

The other Walker siblings’ names – John, Susan and Roger – remain unchanged.

A spokeswoman for the film explained the change, saying: “It was just felt that an audience’s reaction to a name changes over time and Tatty now sits better as a nickname.

“The source of the original name was a children’s story about two characters called Titty Mouse and Tatty Mouse.”

It’s not the first time the name Titty has been changed. In the 1963 television adaptation of Swallows And Amazons, Titty – played by Susan George – was renamed Kitty.

Sophie Neville, who played Titty in the 1974 film starring Virginia McKenna as the children’s mother, gave her approval to the name change.

She told the Daily Telegraph: “I’ve been Titty for the past 42 years. I didn’t get any stick at all over the name in those days.

“But if they have to change it I think Tatty is a good choice, because Mavis Altounyan and her elder sister were known as Titty and Tatty when they sailed so there is a real-life basis for it.”

The actress added: “I’m thrilled that they’re changing it, really, because it makes the new film a bit different.”

Rafe Spall, Kelly Macdonald, Gwendoline Christie, Jessica Hynes and Harry Enfield will star in the new production of Swallows And Amazons, which has started shooting in the Lake District and Yorkshire.

The film, which will be directed by Philippa Lowthorpe, tells the story of four children – played by Dane Hughes, Orla Hill, Bobby McCulloch and Teddie-Rose – camping on their own on a remote island in the middle of a vast lake.

“Watching the young actors learn to sail so brilliantly in our Swallow and Amazon, as we prepare for the shoot, has been a great thrill. I can’t wait to bring this world of pure adventure to life,” said Philippa.

Swallows And Amazons is scheduled to be released in UK cinemas in 2016.