Ancestors do turn quear, as Daisy Ashford says, and when you begin the third novel of a trilogy without knowledge of its forerunners, your fear is not so much that you won’t know who the characters are, for any competent author can introduce you to them; it is that the novelist may have embarked earlier on some grand figurative device that is set to run and run, some complex allegory that you haven’t a hope of coming to grips with. But when you find that, on the first page, a man called Arthur Cornish is presiding over a board meeting at a circular table; that the trust fund over which he presides is discussing an opera called Arthur of Britain, or the Magnanimous Cuckold; then learn in the next chapter that Arthur (not the King) has developed mumps and swollen testicles; that the unfinished opera was allegedly the work of Hoffmann, who in turn was worked over by Offenbach, who provides – ah yes- the title of the book – you do not feel you are in the company of an author who is going to chain you in a pit of obfuscation. ‘The lyre of Orpheus opens the door of the underworld.’ Eureka. Nil desperandum. Light breaks where no sun shines.

It is easier on the reader when the characters themselves are slow on the uptake. If you cannot understand the significance of the sword Cali burn, neither, immediately, can Dr Gunilla Dahl Soot.

‘The symbolismus is very good,' said the Doctor. 'Aha, the sword is also Arthur’s thing – you know,