David Lack taught biology when I was a boarder at Dartington Hall in the 1930s. He was an all-round biologist who later became one of the youngest scientists ever to become a fellow of the Royal Society. While he was teaching us he was also working on his famous book, The Life of the Robin.

The school was a perfect setting both for him and for me, well endowed by its eccentric owners, the Elmhursts, and set in the deep Devonshire countryside in all its pre-war glory. Lessons were always friendly, and there were some interesting people at the school.

But David - or Lack as we used to call him, although we could have called him David - was exceptional. He taught me that the robin was more than a bird; it was also a Marco-Polo-type explorer, and a John Keats of song.

David never had any trouble with discipline, unlike some teachers at Dartington. His lessons were so clear, and in my writing since I have aimed at a similar clarity. He helped me to see biology as a fascinating, rich subject; there was none of that awful cutting up of dead animals that was to come when I went to university.

He was also a gifted artist and very musical. He introduced me to The Beggar’s Opera, singing all the main parts himself. I remember going with a few others - or was it just me? - to see him in his room after he had broken his leg. David was sitting on his bed wearing pyjamas, playing the guitar. You couldn’t get away with that now, but at the time this easy informality seemed perfectly innocent as well as natural. There was a boiled egg on a plate by the side of the bed, which he ate whole. He then asked us to guess why he was doing this, eventually explaining that while he normally left the shell he was consuming it this time because his broken leg needed all the calcium it could get.

He used to take us out at night, listening for birds that often chose to stay silent, though I do remember some corncrakes and a marvellous nightingale. It was because of David that I decided to become a biologist, studying physiology at an all-women’s college. This was a disaster, a definite wrong turn in my life, though I did pick up a wonderful entomologist husband along the way. But that’s the thing about great teachers: they can sometimes inspire you into taking up their discipline just because you like them so much, even though you may really have been much more interested in other subjects that were far less well taught.

What David gave me as a novelist was a strong feeling for terrain, which is why I always try to give my novels a definite sense of place. He was also the gentlest of men: a pacifist up to the war, but changing his mind after working with an ambulance unit. Before that, while he was still at Dartington, he took a year’s leave and went off to the Galapagos Islands.

On his return he wrote another famous book, Darwin’s Finches, with its grand-sounding subtitle, “An Essay on the General Biological Theory of Evolution”. It was a privilege to hear him talking about all the amazing things he saw there. Outwardly shy with other adults, particularly women, he found it easier to relate to children. He married fairly late in life.

He used to dress vaguely: corduroy trousers or flannels and sweaters. His eyes and his hair were pure hazel; when he took us out into the woods on nature walks he melted so much into the background that it was sometimes impossible to spot him.

I kept in touch with him after Dartington; later on he became a devoted Christian, a surprising development for a former progressive schoolteacher.

But for someone like me, coming straight from Vienna, David almost was England. He looked so English, and did such English things. Such a nice man.

Children’s author Eva Ibbotson was talking to Nicholas Tucker

The story so far

1925 Born in Vienna

1933 Settles in Britain and attends Dartington Hall, a progressive boarding school near Totnes, Devon

1942-45 Bedford College, London

From 1955 Builds writing career while bringing up four children in Newcastle, to date producing 10 children’s books and eight novels for adults

2001 Wins the Smarties Prize gold medal for Journey to the River Sea (Macmillan)

2004 The Star of Kazan wins Smarties Prize silver medal, 2005 Carnegie Medal shortlist

2006 Carl Miller’s stage adaptation of Journey to the River Sea is at the Unicorn Theatre, London until March 25. The Beasts of Clawstone Castle is published in paperback in June (Macmillan)