Lionel Jeffries

The Rada-trained star, who was associated with a number of children's classics, was 83.

He was an instantly recognisable figure and became a familiar face in film and TV for decades.

A spokeswoman for his agent, the Liz Hobbs Group, said: "We can confirm he did pass away this morning. It was following a long illness."

Among his many achievements, Jeffries not only directed but scripted The Railway Children.

His also directed The Amazing Mr Blunden, a version of The Water Babies and the Womble movie Wombling Free.

However his on-screen appearances were much more plentiful than his career behind the camera.

He clocked up roles in dozens of films when the British film industry was flourishing with movies such as First Men In The Moon, Camelot and his performance as Grandpa Potts in enduring children's film Chitty Chitty Bang Bang.

During the 1980s and 1990s, he made many TV appearances with guest appearances in shows such as Minder, Inspector Morse, Boon and Lovejoy.

One of his longer fixtures was portraying Grandad in the children's TV series Woof! in 1993.

He also featured in an episode of This Is Your Life in 1971 when Eamonn Andrews surprised him with the red book.

His early hair loss – which he blamed on his Second World War service in Burma – tended to make him look much older than he was. When he was cast in the adaptation of Ian Fleming's Chitty Chitty Bang Bang, he was actually six months younger than his on-screen son Dick Van Dyke, who played Caractacus Potts.

Sally Thomsett, who appeared as one of the lead characters, Phyl, in The Railway Children, said: "He was just totally marvellous and he looked after us like a little family. In fact we were his little family – most of the cast and crew were friends of his. I think that's one of the reasons it was such as a lovely film. He will be greatly missed."

Bernard Cribbins, who played station master Albert Perks in the film, said: "He was a great character. that was his baby, The Railway Children."

And actress Jenny Agutter, who also starred in the film, said: "I have very, very fond memories of working with him. I was 17 when we made the film.

"He was an extraordinary character. Larger than life, wonderfully funny. He very much created a family on set. Just totally dear to work with and just an extraordinary person," she added.

Film director Michael Winner, whose work with Jeffries included A Chorus of Disapproval, also paid tribute.

He said: "I worked with him first in 1965. He's the most marvellous man and he's one of the greatest comic actors this country ever possessed.

"He had an extraordinary talent for eccentric comedy, often playing people who were nutty, who were on the edge of nutty, which basically plays to a lot of people including me.

"But he was a fantastic actor and a great professional. I did two pictures with him, A Chorus of Disapproval and he was in You Must Be Joking, many years apart but he had lost none of his vigour and none of his timing.

"He had the most superb timing, he could make any line interesting and comedic. As far as I'm concerned, I would almost use the word genius for him. I had such admiration for him both as an actor and as a person. It's very tragic to hear he's died. We need people like that."

Liza Goddard, Jeffreys' co-star on children's show Woof!, said: "He was a great character, very funny and I really enjoyed working with him on Woof!"