Pushing and prodding at the song's basic structure with a mix of strings, horns and traditional rock instruments, their ceaseless curiosity is key throughout. He uses the opening title track to limber up, allowing his tremendous band to play themselves in. When the material demands his full attention, however, he absolutely connects. Morrison has been huffing and puffing his way through a slough of mediocrity for nearly two decades now, dishing out perfunctory live shows and bad-tempered blues albums. Miraculously, however, what actually happens is that the music just keeps growing. Neither can you imagine these enigmatic, semi-improvised songs adapting happily to toilet queues and the smell of burger and onions. Astral Weeks is so fragile and dream-like, you worry that if you stare at it too closely it might simply fall apart.

It's a noble ambition but one fraught with pitfalls.

Their old familiar stories are no longer enough: what else have they got up their sleeves? Perhaps that's why Van Morrison decided to dust off Astral Weeks over two nights at the Hollywood Bowl last November: to remind us that, 40 years after being created, this sensational music still lives and breathes. Previously imperious 'classic' albums are now grappling with the ever-increasing demands of the download and deluxe markets. This applies as readily to the old as to the new. Where once there was an accepted hierarchy of bands and albums, these days everything is perpetually shifting.

Van morrison live astral weeks