JUDITH Kerr confesses she has a bit of a hangover, due to a little too much prosecco at a National Literacy Trust party she attended the night before our interview.
Despite a groggy head, the author, who celebrates her 95th birthday in June, is sharp as a knife, with a quick wit that would rival someone half her age.
Not to be too morbid about it, but she is acutely aware she may not have too many years left and says she appreciates life more now – although she does have a 'Do Not Resuscitate' notice should the worst happen.
"The doctor gives you a large piece of paper which he signs, but I often worry whether they'd find it and where to put it. I keep it in the hall. Sometimes I feel like sticking it on the front door but that's a bit much and a bit depressing for visitors.
"Somebody said that the only way is to have 'Do Not Resuscitate' tattooed on your chest. But I never know exactly how to spell 'resuscitate'."
This is the type of humour which peppers the conversation, as we discuss the 50th anniversary of The Tiger Who Came To Tea, her hit children's book that's sold more than five million copies since it was published in 1968 and has spanned generations of children, parents and grandparents.
She has gone on to produces 32 other books, including the Mog series based on the selection of pet cats she's had over the years, and When Hitler Stole Pink Rabbit, a semi-autobiographical tale about a young Jewish girl forced to flee Germany in 1933.
If you're not familiar with The Tiger Who Came To Tea, it's the story of a little girl called Sophie and her extraordinary teatime guest who scoffs all the food in the house. It was inspired by a bedtime story she created for her daughter, after they'd been to the zoo together and seen the tigers.
"I first told this story to my small daughter long ago. She was rather critical of my other stories but used to say, 'Talk the tiger!' So, when she and her brother were both at school and I had more time, I thought I would make it into a picture book – and much to my amazement, here it still is 50 years later."
She says that her publisher, HarperCollins, is throwing her a joint 95th birthday party with the 50-year-old tiger, hopefully with plenty of prosecco.
Kerr is one of the few successful authors who also illustrates her books and has always loved drawing, creating her cats from her own pets over the years.
She had been working as a BBC scriptwriter when she met her husband – the late writer Thomas Nigel Kneale, who wrote the sci-fi series Quatermass – and once she'd had two children, Matthew and Tacy, she wanted to look after them rather than return to the BBC. They moved into a three-storey terraced house in south-west London, in 1962 – where she still lives.
There, in the top-floor study, she created the tiger, Mog, and her other characters in her picture books.
"I'm not a writer. I draw, I went to art school, and that's what I really care about. The book didn't change my life," Kerr continues, "only in the sense that it was my first book published and I was encouraged to do more."
Kerr fled Nazi Germany in 1933. Born in Berlin, she came to England with her family after escaping the Nazis, travelling throughout Switzerland and France as a young girl.
Her father, Alfred, a Jewish theatre critic and satirical writer, had mocked and reviled Hitler and the rising Nazi Party and became a marked man. In 1933, he fled to Zurich, followed soon after by his wife Julia and two children, Michael and Judith.
"I was nearly 10 when we left. What I didn't know at the time is just how hard it was for my parents," she recalls. "It was very hard on them both, but they were very positive. And both my brother and I have always agreed that the childhood we had in Switzerland, France and here was infinitely better than it would have been if Hitler had never happened and we'd stayed in Berlin."
Her husband died in 2006, and she admits work has helped her cope on her own.
"There are things which make life easier. I don't cook. I microwave. For the first time in my life ever, I can work 24 hours a day if I want to. There's nobody else to think about. Of course, I do get lonely but I'm all right if I'm working because that occupies me."
Work is ever-present. She's currently concentrating on another book for eight-to-nine-year-olds, but won't reveal details, while another picture book is coming out in the autumn.
"Going for walks has always helped me to think. Walking is very good physically for the hip, it's cheering, and I love looking at things because if you draw you look at things all the time. And I think about the next bit of work."
:: The Tiger Who Came To Tea 50th Anniversary Edition by Judith Kerr is published by HarperCollins, priced £6.99.
