I spoke to a number of Plath biographers and friends after speaking to Elizabeth Sigmund (including Al Alvarez, Carl Rollyson and Ronald Hyme). They confirmed the substance of what she said – in particular, that Plath had not wanted The Bell Jar to go out under her own name while her mother was still alive. Elizabeth also produced a scan of the letter from Charles Monteith explaining that Faber was unaware that those were Sylvia's wishes.

However, since it was almost 50 years after the event, and Faber were consequently unable to supply any further information, it became clear that the only person who really knew about the omission of the dedication to Elizabeth and her husband from the 1966 edition was Olwyn Hughes. Fortunately, she agreed to speak to me and set down her side of the story.

The following conversation comes verbatim, from my notes. I would just like to add that in spite of the force of many of her words, that Olwyn seemed good-humoured and peculiarly charming. It might help if you imagine the following spoken in a warm Yorkshire accent:

I want to ask about the name change on The Bell Jar?

She [Plath] was very worried about it because she thought it was going to upset her mother. It was a nightmare for her, actually. She got quite paranoid about it towards the end. And then she was disappointed when it came out and it didn't have a very good press.

Sorry, I meant the decision to actually use her name?

The decision to use her name was taken after her death, when everybody really seemed to know it was by her. Her friends all knew. There seemed no point in not publishing under her own name.

I've been speaking to Elizabeth Sigmund …

Oh God, have you? I mean gabble, gabble, gabble, gabble … Has she some new stories for you?

She was telling me about the dedication.

She [Plath] dedicated it to Elizabeth and her husband, because she didn't want the London lot to know – you know, her real friends. She didn't know Elizabeth very well, you know. Although according to Elizabeth … Anyway, we've had enough of Elizabeth … [Goes on to suggest that Elizabeth Sigmund's accounts of events were not always reliable.] What has she told you?

She was saying she was left off the 1966 edition …

Oh yes, that was a Faber error. She thought that was a terrible plot of Ted's. I don't know what that was about. It was just Faber left it off. These things happen in publishing.

She also said that she was sure that Sylvia Plath never wanted it published under her own name.

Well, yes. She didn't want to upset her mother. What it tells, The Bell Jar, is a watered down version of her own breakdown. And that was also very painful to her – quite apart from the fact that there's a passage in the book that's rather unpleasant for her mother to read, about the mother's snoring or something. Sylvia got very het up about the book because I think it was so self-revelatory. In a way she liked that – and in a way she didn't.

That's certainly what I think happened with Ariel – her whole trauma, her father's death upsurged. I think writing The Bell Jar provoked that … And all that traumatic material that came up in Ariel. I think it caused her a lot of aggro. She was a very agonised lady. She had to battle to live every day – as you might glean from The Bell Jar. When I read it after she died, I just wept.

But people don't realise. They didn't then, even. She didn't always show how troubled she was – but she had no inner calm at all. The Bell Jar deals with the beginnings of the trouble. Then she spent the rest of her life dreading its return.

Oh God.

The nonsense that has continued to be written about the story is shocking to me. Sylvia wasn't the innocent victim, or half so helpless as she's been made out to be. You just have to look at some of her poetry. She was just nasty in the last poem about her husband and father ["Daddy"]. She was vicious and I think a bit crazy. I watched her going through her torment and it was agony. But Ted was so taken with her. I don't know why. I don't know how she did it … Especially because I don't think that she could control the negativity in herself. You've got to remember the venom that Sylvia dished out.

I don't think anyone has taken into account how injurious the rubbish that's been written about her has been. What the feminists don't take into account was how much psychological trouble she was in. She was a very difficult woman with a very difficult personality. She was horribly unjust both to her mother and to Ted. And I'm sick of reading that he left her for Assia – that's all you get whenever his name is mentioned. Assia. But Ted didn't walk out.

It was actually a friend of Assia's who told Sylvia. She rang her up and thought maybe she was helping her, or wanted to warn her, or something, I don't know. But this person had no idea how on edge Sylvia was. That she wouldn't be able to cope with this information. And so when Ted next went down [to their house in Devon] she was in a rage and threw him out.

I wish the newspapers would get it right. He didn't even know that Sylvia would find out about Assia. He'd done everything he could to be very discreet. It was just one of those things … And of course Sylvia, when she did hear about it, it reminded her of all her terrors about abandonment and everything else. She wouldn't listen to anything but separation and divorce. But he didn't leave her for Assia. That's just not true. He was actually staying on friends' floors in London until he got a little place by himself. He certainly wasn't living with Assia.

Oh and she took all the money out of their bank account. She was a monster actually.

So what about changing the byline. How was that decision taken?

What people want after they're dead. That just goes. And nobody was going to be able to keep the secret about who wrote the book for decades. Besides it was a very good little novel.

She was disappointed when she was alive – she was worried about the Jennifer Dawson's novel The Ha-Ha – which was similar and got a lot more attention at the time. She hadn't the calm in her necessary to cope with it.

There was all that martyr talk, even after Ted's death … in America there were a couple of biographies that were terribly bad. They didn't take account of the fact that Ted had nursed the bloody woman for seven years. The patience that he had with her!

Of course, I didn't quite understand or realise that she was quite sick. We didn't know as much about psychology in those days. But let me tell you about one thing. Ted was meeting an old teacher once – and she just ran off. He had to run out onto the moors after her. She did that in front of his old teacher. Can you imagine? And he lived with it.

And when you read her journals – there were some very dark things in there … And there was a furore when they first came out that they were cut. And a few things were taken out – mainly at the request of her mother, but otherwise he did nothing. But there was this great furore and suggestion that there was an attempt to hide things. But what were the secrets?

Of course, nobody actually read the journals! They were too busy focusing on what they thought wasn't there. And if they did read it properly they'd have found a very damaged girl. A very mixed-up girl. You just had to look at the dreams she described. Her dreams were bad enough to spoil your own.

I understood then how powerful a grouping the feminists can be. And how it still goes on. This crap. No matter what goes on, you can't counter it. They just lie, and if they find themselves in the wrong, they just ignore it.

I'm collecting all the press I've got and giving it to Pembroke College. There was one thing, by someone from the Guardian that I found really upsetting … Katherine … I can't remember her name. All that martyr stuff. It was just a few days after Ted died that it came out and I thought aren't The Guardian ashamed of themselves? [We're unable to pin down the piece to which she's referring. There's an article by Katharine Viner on the Plath diaries from 2000, but this was 18 months after Hughes' death.]

I don't have any time for them, really the press. I don't normally talk to journalists.

I must be very fortunate ...

Hmm. Well. I wish you'd print what I actually say. You know I would love to talk to some journalist and they could take me seriously – and actually put down what I say. That would be the first time.