The last person who saw Sylvia alive was the neighbour in the flat below hers in Fitzroy Road, Primrose Hill. She asked him for some airmail stamps a few hours before her suicide. If she needed stamps, there must have been a last letter. The story at the party in New York was that it was a suicide note addressed to her mother, Aurelia; that at some point it went astray; and that it named the other man.

Hughes did not kill Plath. Nor did the other man. Mental illness killed her. But biographic closure will not be achieved until we know what was in the last letter. I recently heard of a private collector who is alleged to own “literary jewels such as a signed first edition of James Joyce’s Ulysses, Vladimir Nabokov’s personal, annotated copy of Lolita, and a letter written by Plath the day before the American poet killed herself”. He has not replied to my request to take a look at it.

• Jonathan Bate’s Ted Hughes: The Unauthorised Life is published by Harper Collins.

The emphasis in my novel Capriccio: the Haunting of Sylvia Plath, is on the insidious influence of Sylvia’s suicide on both Ted Hughes and Assia Wevill. I’ve invented all journal entries and letters, and changed the names of any characters still living. This is my imagined letter which Sylvia may have written the day she died, and which has never been found.

To the woman who stole my husband,

I cannot bear to write your name; its very sound is a hiss from the tongue of a serpent. You snaked your way into our lives and destroyed all that was once wholesome and fertile, and changed my husband from a god to a devil. Here is the gift you have wished for, freeing him to be yours. But rest assured, he will never love you, or your bastard child, as he’s loved me and our children. With this act I curse you forever. I will always be between you, watching and waiting. The day will come when you and yours will join me in hell.

                                                            Sylvia

          Note to my Readers: This novel is a work of Fiction, based on the true story of Sylvia Plath, Ted Hughes, and the woman who came between them – Assia Gutmann Wevill.

At the time she was supposed to have penned this letter,  Sylvia was severely disturbed and suffering from the effects of a medication which may have been wrongly prescribed. She had begged for stamps from her neighbour downstairs, who was the last to see her alive. My fictional account of the last letter has her directing all her bitterness towards Assia who she blamed for all her misery. To my knowledge, no one found the last letter Sylvia wrote and of which she needed the stamps. She also left a note for Ted, whose contents were never revealed, and the doctor’s phone number, indicating she may have wanted to be saved.

see also http://www.sylviaplath.info “A Celebration This is: a Website for Sylvia Plath”