"Can you imagine me hanging naked off the back of a policeman in 1966?" asks Donovan. He leaves a moment for this delightful image to sink in, then continues a lengthy anecdote about his drug bust. All his stories seem to involve either marijuana or George Harrison, and this one has both. Perhaps he is trying to establish his outlaw credentials - or perhaps, as it often seems tonight, he is simply saying whatever comes into his head.

Donovan Leitch has never been cool. Regarded first as a gauche Dylan imitator, then as a gauche hippie, he has rarely been given full credit for the psychedelic strangeness of Sunshine Superman or Barabajagal. If he had lost his mind on acid in 1969, he would surely now be regarded as a cult visionary - but he didn't. At the QEH, ageing flower children outnumber younger converts by a considerable margin.

This show is called Celebrating '64, and Donovan's version of the 1960s is one without dark undercurrents; it's like Altamont never happened. Bearing a green guitar and a harmonica, his face framed by a great fuzzy halo of hair, he urges: "Let's open our hearts, intoxicate ourselves with spirit." He proceeds to share a Cherokee parable about war, introduce us to his guitar ("Her name is Kelly") and play the kazoo, although not all at the same time.

After the interval (it's a three-hour show), he reappears wearing a dressing gown and sings Hurdy Gurdy Man in an unidentifiable accent. The man is technically Scottish, but his voice is a law unto itself. He talks about somewhere called "Americay", and appears to dedicate the song Josie to the rapper Jay-Z.

You could laugh, of course, but the 57-year-old is disarmingly childlike, a bona fide hippie who retains his wide-eyed idealism. As he leads the crowd in a mantra-like round of Happiness Runs, you're not sure whether he should be put in charge of a children's TV show or a cult. Donovan may never be cool, but you're rather glad he's still around.