As far as Henry Pluckrose was concerned, a classroom was not something with four walls and a blackboard. For the London primary headteacher, the entire capital was his classroom. Life was a lesson for pupils to learn, school merely something that helped them understand it.
Henry Arthur Pluckrose was born in October 1931. His first six years were spent in a tiny south London flat, the toilet outdoors, the house illuminated only by gaslight. With his mother unable to cope with the demands of her young family, Henry was raised primarily by his older sisters.
After school, his national-service years were spent in the education corps, helping servicemen improve their literacy. He relished the work and, on discharge, enrolled in a teacher-training course at London's College of St Mark and St John.
His first job, in 1959, was at John Ruskin primary in south London. He had been drawn to the school's liberal ethos: its open-minded head allowed free rein to his young teacher's newfangled ideas.
Education, Mr Pluckrose believed, was about hands-on experience of the outside world. He would take pupils on field trips to museums, churches and parks, bringing the knowledge gained back into the classroom to illuminate more conventional lessons.
And, unlike many contemporaries, he wanted the classroom to be a place of creativity and creation. A natural raconteur, he would turn maths or science lessons into storytelling sessions. Many of these stories eventually found a wider audience in the children's books he later wrote and published.
In 1968, he was appointed head of Prior Weston, a new school on the edge of London's Barbican complex. The school quickly became a showcase for its head's ideas. He drew liberally on the area's rich history: Shrove Tuesday would be spent tossing pancakes in Paternoster Square; the Christmas fete would be held at the Barbican church where - as he pointed out to pupils - Milton married and Cromwell was buried. And, every year, Mr Pluckrose would write a Christmas play for his pupils, drawing once more on local history. One script, for example, dealt with the life of Dr Barnardo; another told the story of mothers leaving their children in Coram's Fields orphanage.
He had begun delivering workshops on creativity at London University's Institute of Education in the early 1960s. This led to book commissions, as well as more and more workshops. These, too, were filled with hands-on materials: paints, glues and modelling clay. And all pupils - whether adults or children - referred to their teacher as "Henry". He, meanwhile, called himself a "journeyman-teacher".
But he was no woolly-minded liberal. There was definite order and structure at Prior Weston. Teachers were expected to work hard: every lunchtime, for example, they would gather to discuss that morning's lessons. Naturally courteous and phlegmatic, he disapproved of ill temper in others. But he had a talent for the thoughtful gesture - a Christmas card to a long-departed colleague, a poem sent to a former pupil - that made staff and pupils feel immediately valued.
In 1975, he published Open School, Open Society, his manifesto for education. It garnered him an international reputation: whenever foreign documentary-makers were looking for a progressive English case-study school, they inevitably arrived at Prior Weston. One such Swedish documentary was so well received that Mr Pluckrose became a minor Scandinavian celebrity, invited for repeated lectures.
He retired his headship in 1984. This was not, however, the end of his career in education: he served on a series of councils, including the National Book League and the National Trust, and continued to publish books. However, outside the classroom, he was always something of a fish out of water, "as if he wasn't quite sure what to do with himself", a colleague remarked.
In 1986, he joined the Royal Opera House education department, heralding the sudden involvement of a surprising number of Scandinavian teachers. Never comfortable with technology, he ignored the computer that was installed on his desk, instead writing out all documents in fountain pen.
Parkinson's disease, therefore, struck particularly hard. But - once again seeking lessons from life - he turned this experience into poetry, some of which was published. "I have discovered," he said, "the joy which comes from having time to stand and stare."
Henry Pluckrose died on 6 April. He is survived by his children, Elspeth, Hilary and Patrick, and by his partner, Hilary Devonshire.