Last year, on his most recent visit to London, Merce Cunningham took a curtain call on the opening night of his company’s season at the Barbican. Nothing remarkable in that, except that the American choreographer was then 89 years old, frail, arthritic and confined to a wheelchair. He could have hidden away in the wings and saved the applause for his wonderful dancers, but perhaps he sensed that he owed this last look to a loyal and adoring audience. Or perhaps, as I like to think, he was savouring the vindication of a career that courted almost as much damnation as praise.

Brilliant, eccentric, provocative, a fraud: Cunningham, who died this week at the age of 90, was called all these things in his day. But to his fans he was that rare creature, an artist who pursued a single aesthetic and refused to bend with the wind. He loved movement and he looked for it everywhere, even in the beating of a butterfly’s wings. And he put that passion for pure dance on stage time and time again. “I am fascinated by the possibility of something I haven’t found yet,” he once told me.

By the time I met Cunningham he was 83 and a very deceptive presence. You could easily mistake him for a benign pensioner who liked a quiet life and drew birds in his spare time. In reality he was one of the most radical and wilful choreographers the world has known.

It was sad to see his once-powerful gait reduced to a snail’s pace (this was before the wheelchair). Arthritis, he explained, caused by all those years of dancing on concrete stages. But for a man who used to inflame traditionalists with his “crackpot ideas” (their words, not mine!), Cunningham was surprisingly mellow and almost preternaturally gracious. Around him, everyone at the New York-based Merce Cunningham Dance Company conspired to make his life as easy as possible to let him get on with the business of making dances.

And what dances. Cunningham was full of them, rigorous, idiosyncratic and often downright gorgeous ones. His quest for fresh perspectives on movement never faltered. He was an unreconstructed revolutionary who remained true to his avant-garde instincts through more than half a century of making work. Even as an octogenarian, newly converted to the thrill of computer-assisted choreography, he was at the forefront of dance innovation.

His fundamental premise (for which you can thank the composer John Cage, Cunningham’s long-time partner) is simple: music and dance don’t need to speak to each other.

So choreography, music (usually electronic) and design (often by famous painters) are all created in isolation and meet only in performance. If they do find harmony together, it’s serendipitous; if they don’t, it’s irrelevant.

Sometimes people find it difficult to relate to dance that has no stories to tell or no melodies to dictate the pace. In the early days audiences walked out (if they bothered to show up at all); in Paris (when his company started European touring in the 1960s) they threw tomatoes. Yet the great joy of watching the best Cunningham dances lies in their lively unpredictability, their glorious illogic, their multiple focal points, their liberating freedom (a dance means what you want it to mean), and the magical unplanned moments when steps, score and setting all seem to come together.

I once asked him if he felt that the world had finally come round to his way of thinking. “Yes, I do,” he said. “It isn’t just because they’ve come to see me, because they didn’t. But things in their lives have changed which somehow work with some of these ideas I have pursued. They see television now with four or five things going on at once.

When I did that on stage people said, ‘What are you doing?’ Now it’s part of their lives.”

We have been lucky to have seen so much of his company — 11 visits to London in the past 20 years alone. And next year Dance Umbrella and the Barbican are planning to present Nearly Ninety, Cunningham’s last creation (the title says it all). In June this year the Cunningham Dance Foundation announced that, after his death, the company would close after undertaking a two-year international tour. Then everything, from costumes and props to audio and video recordings, will revert to a trust that will hold the copyright to all his choreography. So unlike the nasty inheritance squabble that followed the death of Martha Graham (for whom Cunningham once danced), his singular legacy looks set to be well protected for future generations.

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