The estate of Ted Hughes has hit back at claims after a biographer abandoned plans to publish his book with Hughes’s poetry publisher, Faber. According to reports in the Sunday Times and the Guardian, the Shakespeare scholar Jonathan Bate, who began working on a biography of the former poet laureate in 2010, said that Hughes’s estate had barred him from archives, asked that he return photocopies of privately held documents, and withdrawn his right to quote extensively from the poet's work – described by the professor as "an essential aspect of serious scholarship".

In reply, Damon Parker, spokesman and solicitor for the Ted Hughes estate, said: "Concerns were expressed to Professor Bate as early as 2010 that he might be straying from the remit agreed for his book. He repeatedly resisted all requests to see some of his work in progress, as agreed. His comments to the press in recent days have confirmed the concerns that the estate had long held."

Hughes was married to the equally renowned poet Sylvia Plath, who took her own life in 1963. Birthday Letters, a collection of poems about his relationship with Plath, was published shortly before his death in 1998. Before Hughes died, he restricted access to Plath’s journals and drafts, and burned her final diary. The poet Frieda Hughes, daughter of Ted Hughes and Plath, did not allow her mother’s poetry to be used in the 2003 film Sylvia, starring Gwyneth Paltrow.

The Sunday Times reported that while the book was not to be an authorised biography, Hughes's widow Carol had given her blessing. She was also said to have offered “blanket permission” to photocopy materials from the Hughes archive, which the British Library purchased for £500,000 in 2008, with the estate retaining copyright.

The Guardian reported Bate as saying that the decision to withdraw support came "completely out of the blue", though the estate was becoming "impatient" to see more of his work. Just days before Bate was due to send 100,000 words, the estate informed him that he was no longer able to quote from the Hughes archive. The Oxford University professor was quoted in the Guardian as suggesting that the family mighthave been worried by the prospect of revelations about the poet's private life.

"I have discovered some things that surprised even Carol and Olwyn, Ted's sister, so there may be more surprises to come," he said. His researches have so far uncovered many unpublished poems, evidence that Hughes was working on Birthday Letters almost from the day Sylvia Plath died, and a hitherto unseen diary for the last week of her life, which reveals "how close they were to being reconciled".

In its reply, the estate's spokesman added: "It is curious that he should have taken his sense of grievance to the press when he had written to Carol Hughes only a few weeks ago, after his contract with Faber was ended by mutual consent, that: 'I will not go into print or speak to journalists on the subject of the changed status of my work.' Clearly he has chosen to break his own self-imposed silence. He did so last Sunday and Monday with the inflammatory claim that the reason he was dropped was due to concern that he might unearth 'revelations about (the poet's) private life'.

"Carol Hughes totally rejects this claim, insisting that there is no 'secret being guarded' as Professor Bate speculates. The archive is open to public inspection. And she dismisses as 'ridiculous' his claim here that he has 'discovered some things that surprised even Carol … so there may be more surprises to come'. Mrs Hughes says that nothing discovered by him has surprised her. And the poet's widow strongly rejects his suggestion that she 'unnecessarily reneged' on the agreement for him to write a literary life of the poet."

Bate's contract with Faber, which also publishes Ted Hughes's poetry, was cancelled by mutual consent. The professor said he is now rewriting the biography for HarperCollins, and cannot be "made to forget the things … [already] read in private archives". With the blanket permission to quote from the publicly available Hughes archive now withdrawn, he has been consulting with lawyers about how he may paraphrase the poet's work. "There is, not least, a genuine 'public interest' question around the right to quote from material that has been purchased by the public purse and deposited in a public collection such as the British Library," he said.