It became clear to me, through talking to a number of people who knew Jelly and Adila, that the sisters believed 100 per cent in the ‘spirit messages’ they were receiving. That others were less convinced is unsurprising. Baron Erik Palmstierna’s book, Horizons of Immortality, contains transcripts of the messages, as does The Sisters d’Arányi.

The hiatus between the arrival of the first ‘message’ and Jelly’s efforts to start looking for the concerto is fictional: it is a chance to explore the conflict between her passion for giving charity concerts, and the pull of so-called ‘psychical research’, which must have been at odds with her Christian faith (and Adila’s). The culmination of Jelly’s love for simply bringing music to her audience is the scene at the Savoy – which, along with her fall-out with Adila, is also entirely fictional. The cathedral tour, though, is very much real: Jelly’s first cathedral tour in 1933 raised £2,500, including a government grant of £1,000 (the equivalent of around £118,250 in 2016). She gave a further tour in 1934 and in summer 1938 performed a recital at St Paul’s Cathedral in London.

Jelly never married. The account of her friendship with Sep Kelly is based as far as possible on reality. The relationship with Tom Spring-Rice, however, is a matter of reading between the lines in The Sisters d’Arányi. The glass-game session with Anna Robertson that produced the first communication from ‘Schumann’ was inspired, according to Macleod, by the end of a love affair; with whom, we don’t know. Tom Spring-Rice, Lord Monteagle, died in a Dublin nursing home in autumn 1934. Macleod makes it clear that Jelly was much affected by his death, mourned him deeply, and sustained a succession of illnesses and injuries at this time. The nature of Adila’s friendship with Palmstierna is not documented.

I have it on good authority from Jelly’s family that Moshe Menuhin did give Jelly harsh words about her involvement the Schumann concerto, though the precise details of where, when and how are not clear. He has been depicted to me, by those who knew him well, as a difficult, somewhat pugnacious character.

A few of the characters are purely fictional: Ulli Schultheiss, the critic James Gambrell, the pianist Bernhard Rabinovich, Lady Chiltington, Charles and Mary Southern, Fräulein Kammerling, Maria the maid and the journalist Lionel Hartshaw.

The letters from Sir Donald Francis Tovey, Elisabeth Joachim and Eugenie Schumann, plus the published articles mentioned in the novel, are all real (and the reviewer of Palmstierna’s book, Harry Price, has been accorded his own TV film). Eugenie Schumann’s extended letter was published in The Times. Letters to Jelly from Tom and obviously from Ulli are invented.