Lady Archer said last night it would be ''unjust'' if David Blunkett blocked her husband's application for early release from prison.

The Sunday Mirror reported that a senior Home Office official had written to the commissioner for correctional services to say that Mr Blunkett did not want Jeffrey Archer released.

The disgraced Tory peer, who is serving a four-year sentence for perjury, becomes eligible for parole in a few weeks' time.

The Home Office denounced the document as a forgery, saying no-one in the department had any record of it.

However, Lady Archer said: ''I am perturbed by this report, and I am seeking clarification from the Home Office and the Parole Board,'' she said.

''The great majority of prisoners' applications for early release on parole succeed, and so far Jeffrey's application for parole has been going very smoothly.

''Is the home secretary now able to override this process? It would be unjust if he were to intervene once more in Jeffrey's treatment by the Prison Service or so to intervene in Jeffrey's application for parole.''

The Home Office said Mr Blunkett had never expressed any opinion on whether Archer should be given parole.

However, the Sunday Mirror stood by its story.

A spokesman said: ''We have no doubt the correspondence exists in which the Home Office is making it clear that they do not want Jeffrey Archer released on parole next month.''

The document obtained by the newspaper appears to be a letter from a named Whitehall civil servant to Martin Narey, former Prison Service director general, in his current role

as commissioner for correctional services.

The document reads: ''As you are aware Jeffrey Archer is approaching the half way part of this sentence. This is of concern to the home secretary because Archer could become eligible for parole having served half of his sentence.

''Given the large amount of press interest in Archer and the difficulties this has caused, the home secretary and your department, we are keen to see that Archer is not immediately released at the halfway point of the sentence.

''We are keen to see that Archer does not profit from his time in custody. The home secretary is keen to avoid any embarrassment to himself personally or the department, if Archer was seen to profit from his crimes or time in prison.

''Please communicate your views on this subject to my office as soon as possible so I may liaise with the Parole Board to prevent the imminent release of Archer, or publication of any further books by the inmate.''

A Home Office spokesman said: ''This letter appears to be a forgery.

''The home secretary has never expressed any opinion, either publicly or privately, on Jeffrey Archer's Parole Board hearing, and the Home Office has no record of the letter from (the named official) on which this story is based.''

Archer was given a four-year term in July 2001 for perjury and perverting the course of justice in relation to a libel case.