After 50 years Chitty Chitty is still banging!

The classic children’s film celebrates its golden anniversary this year but the origins of the story were sown a decade earlier, when James Bond’s creator Ian Fleming invented tales of a flying car with a mind of its own for his son Caspar.

Fleming died before the book was published in 1964, and the tragic Caspar took his own life in 1975. There are happier connections for Ty Jeffries, the son of Lionel.

A young boy at the time of the film’s shooting, he remembers visiting the set at Pinewood with his father and the stars who became friends and neighbours.

A singer and songwriter himself, currently in residency at London’s Brasserie Zedel as the ageing Las Vegas cabaret artiste Miss Hope Springs, Jeffries remembers his father brushing up on the music for the film at home.

“I remember when he came home with the reel-to-reel tape with the songs and rehearsing to the backing tracks,” says Jeffries, “He was naturally musical.

Both his parents were in the Salvation Army so he grew up around that, singing hymns. He had a good voice. I remember him singing September Song beautifully on The Dave Allen Show.” One of the musical numbers nearly brought Lionel’s life to a premature end though.

The scene where Grandpa Potts sings Posh! in his shed while it is winched away by Baron Bomburst’s Zeppelin required Jeffries and the structure to be dipped into a real tank of water at Pinewood.

“At one point, it went right in and he ingested a lot of water into his lungs,” Ty recalls, “That gave him a nasty turn.”

Ty also remembers parties at the mansion rented by Dick Van Dyke during filming: “I remember being absolutely gobsmacked by the gold-plated swan taps in the bathroom.”

Jeffries Junior became friendly with Van Dyke’s sons; one of whom, Barry, would go on to appear with his father in Diagnosis: Murder.

While most of those involved with the film were busy enjoying themselves, the film’s co-writer and director Ken Hughes was unhappy, despite its huge success.

His other collaboration with Jeffries, The Trials Of Oscar Wilde, was his proudest achievement as a director. “I didn’t enjoy making Chitty Chitty Bang Bang,” he said. “The film made a lot of money but that doesn’t really make me feel any better about it.”

There were contrasts at work with the casting. Jeffries, often known for playing hard, sometimes brutal, men and authoritarians such as the Marquess of Queensberry, shone as the lovable eccentric Grandpa Potts.

Later, he would direct The Railway Children and The Amazing Mr Blunden, both acclaimed films for children. “He was very good with kids,” remembers Ty, “particularly his grandchildren.

“He would get into their world and talk to them on their level, but not in a childish way. Roald Dahl, who worked on the script, was a great family friend and I think he had that sort of ability too.”

Meanwhile, the Australian actor, dancer and choreographer Robert Helpmann, who played the sinister Child Catcher, is remembered by the child actors as a kindly figure, despite his reputation as a hard taskmaster in dance.

When he died in 1986, Adrian Hall and Heather Ripley – who played Jeremy and Jemima – attended his funeral in Australia.

When the film was ready for release, the Daily Express ran a competition to win Truly Scrumptious’s car, a specially-built replica 1909 Humber with a modern Ford V4 engine.

Readers were invited to imagine they were selling it in the manner of a 1968 car dealer by choosing eight selling points from a selection of 14.

They included “All-round visibility” “An ‘over the hedge’ view on corners”, “Extensive brass work”, “Distinctive tone, bulb type ‘serpentine’ horn” and “Genuine ‘fresh-air’ ventilation”.

The winner was veteran car enthusiast Reginald Harwood of Harrow, and the car has since become part of the Beaulieu Motor Museum collection.

The main Chitty Chitty Bang Bang car, created by the film’s designer Ken Adam and cartoonist Rowland Emett, was built with a Ford V6 engine to be legally roadworthy and registered GEN11.

It is now owned by Sir Peter Jackson, director of The Lord Of The Rings films. Of the people who appeared in the film, Dick Van Dyke remains very boyish for 92, while Sally Ann Howes, who played Truly Scrumptious, lives in New York with her husband Douglas Rae.

Adrian Hall, who played Jeremy Potts, is now principal of the Academy of Live and Recorded Arts in London. Heather Ripley decided against staying in acting and became an environmental campaigner.

After years of being uncomfortable when recognised as Jemima Potts, she is now working on a book about her experiences on the film.

● For details of Ty Jeffries’s shows, visit misshopesprings.com