Christmas would lack much of its sparkle without the magical cartoon characters created by Sussex author Raymond Briggs.

The picture-book author brought us The Snowman that comes to life and whisks a little boy off to the North Pole and the grumpy Father Christmas who resents his job and mutters, "Another bloomin' Christmas".

Both these stories were turned into celebrated animated films, which have become as traditional a part of the British Christmas as turkey and tinsel.

Now Raymond - who has lived at Westmeston, at the foot of the Downs near Lewes, for 31 years - has delivered another festive gift.

He has dreamed up a new story called Ivor The Invisible about a naughty, invisible giant who turns up in a boy's bedroom and creates mayhem.

The resulting animated cartoon will be screened by Channel 4 on Christmas Eve and is a rather offbeat tale.

You can't see the main character, it is never revealed how tall he is and the he-giant seems to turn into a she-giant, called Beryl, mid-way through the story.

It would take an unusual adult to dream up such an idea.

Raymond, 67, has been described as gloomy, with a dry sense of humour.

He is not a fan of Christmas and said: "It's just an awful heavyweight thing. I'd like it if it was treated a bit more lightly.

"It starts too early - the shops were full of Christmas decorations long ago. Then you've got the huge business of all sorts of people coming for meals. Many of them are not particularly welcome.

"They are sort of duty things, you've got to have so-and-so and everyone heaves a sigh of relief when it's over."

Then there is the subject of children.

Raymond is a children's author but that doesn't mean he has to like them all. He said: "You can't generalise. Some of them are delightful and some are absolutely poisonous."

Since he has no offspring himself, he added: "I'm no authority on children. I don't know what they should or shouldn't do. I don't think about them."

Other pet hates include travelling abroad and the works of a certain writer called J K Rowling.

Raymond does try to be up-beat about the Harry Potter author, saying of her fame: "I'm delighted because it just shows that books are still a vital force in the world. It came to this success purely through the written word. She hand-wrote this stuff, which has set the world alight.

"I personally don't like it very much."

He has just started trying to read a Harry Potter book again.

He said: "I think I have almost got a duty to find out what this is all about. I thought what little I've read of Rowling was a bit banal, really."

Raymond lives alone in a rambling bungalow on the South Downs. He has a sad history in many ways. He was an only child, who grew up in south London, and his parents did not live long enough to witness his phenomenal success.

His mother died of leukaemia in 1971 and, nine-months later, his milkman father died of stomach cancer.

Then on Christmas Eve, 1972, his wife, the artist Jean Briggs, was taken ill and diagnosed with leukaemia. She died on February 21, 1973.

Raymond and his late wife moved to Sussex because they could not afford to buy a house in London and first lived in Burgess Hill.

For 26 years, he taught illustration at the then-Brighton Polytechnic. But 14 years ago he gave up to work full-time on his books.

It was during the dreadful time when his wife was ill that Raymond penned his funny Father Christmas story and he has recalled taking this work-in-progress along when he visited Jean in hospital.

But all is not gloomy in his life. For many years now he has had a girlfriend called Liz and clearly adores her three grandchildren, aged four, six and eight.

He said: "I love being with them. It's terrific fun. They just play silly games and climb all over me and bash me up, usually."

However, it makes perfect sense for Raymond and his lady friend to have separate homes - for she is tidy and he is not.

Quite how bad his messiness is, becomes clear when he begins talking about his habit of collecting things.

At present, he is hoarding plastic filter coffee lids.

He said: "I collect them and I'm making a great pile of them in the bathroom. They are stacked on a corner of the bath against the wall and the pile is six feet high at the moment. It is a work of art."

He has also gone through phases of collecting hand-made iron tools and, even more bizarrely, electric fires.

But Raymond does not approve of his habit and said: "I am trying to give up collecting because I don't think it is very healthy, quite honestly.

"I think it is a slightly mad and pointless thing to do."

Not that the author minds being thought of as an eccentric. He delightedly recounts how Liz's granddaughter Connie announced one day at dinner, "Raymond is not a normal person".

At the time, the little girl was three-and-a-half and Raymond, who had done nothing that he knows of to prompt the comment, said: "I thought that was fantastic for her to come out with the words 'normal' and 'person'. She didn't say, 'Raymond is a funny man'.

"I've got that phrase written on the door and I'm going to have it on my tombstone. It was the best compliment of all time."

Ivor The Invisible will be screened on Channel 4 on Christmas Eve. A book, called Ivor The Invisible, is published by Channel 4 Books, priced £10.99 and is available now.