Although his books have sold more than 85 million copies, beloved author Terry Pratchett gestured at his trademark hat and dapper striped blazer, commenting in mock-crotchety style, “Yes, I’m a millionaire – you can tell by my well-cut clothing. I feed the chickens in these!”

Pratchett’s assistant Rob Wilkins and producer Rod Brown accompanied him on stage, teasing the packed audience of fans by reading from the new Discworld book Raising Steam and dropping hints about future film and television spinoff projects.

The shadow of mortality hangs over Pratchett – his remark, “So many things to write, so little time!” was met with a charged silence and an audible gulp from one audience member.

Wilkins began a story with “Terry always said…” and was sharply cut off with a snappy “Still says!” Although he moved slowly and occasionally grasped for a word or concept, his compelling aura was undimmed.

Finally, he was asked, “How are you?”

Pratchett explained that despite his PCA Alzheimer’s, his new voice-to-text computer programme made him more prolific than ever.

“I have no fear whatsoever of dying,” he declared reassuringly, “and once you have no fear of dying, the world is your mollusc.”

The audience rose in a standing ovation.