At 80, SF author M John Harrison is producing some of his best work. He talks about finding his voice, alien intelligence and the advice from Iain Banks that still spurs him on Three years ago, in a greasy spoon on the fringes of the City of London, M John Harrison – Mike to his friends – told me about the novel he was working on. Rather than describing its plot or characters, he spoke purely about the challenge the book presented to him as a writer. With this one, he said, he wanted to push thi