Emma Howie, 35, was labelled a "grass" and sent a wreath in the post after giving evidence in a high-profile employment tribunal which saw the Prison Service pay out almost £500,000 in compensation to whistleblower Carol Lingard.

Mrs Lingard was hounded out of a promising career when she revealed that one of her superiors had attempted to 'fit up' a sex offender at Wakefield Prison.

Ms Howie, from Wakefield, won her case in January. She claimed she was blanked and ignored by staff at the prison, despite changes supposed to have been brought in after Mrs Lingard's tribunal in 2004.

The tribunal said the way her complaint was handled was a "travesty of what should have occurred" and the Prison Service had done "everything it could... to rub salt into the wounds".

After the Lingard decision, the Director General of the Prison Service, Phil Wheatley, said the way she had been treated was "indefensible" and one which he did not "ever want to recur again at Wakefield or anywhere else".

He said the Prison Service needed to "learn the lessons and sharpen up our response to those sorts of complaints".

But the employment tribunal has now noted that the Prison Service "uttered fine words but failed to carry those through into meaningful actions".

Ms Howie was victimised by other officers at the jail as a consequence of giving evidence of wrongdoing at the prison.

She raised a complaint to management about her treatment, in particular the leaking of a confidential document about her by a Prison Officers' Association (POA) official.

But the tribunal found that the officer Ms Howie had accused "was effectively allowed to escape entirely free of punishment for seriously unacceptable conduct".

In a scathing judgment the tribunal stated that it was "astonished" adding: "There appears to us to be a substantial reluctance on the part of the senior management of HM Prison Wakefield to take any action which might offend the POA in any matter."

The tribunal also found that attempts to explain the handling of the investigation were "entirely inadequate" and officers "lied and deliberately lied".

Ms Howie's solicitor John Sturzaker, of Russell Jones & Walker, said: "The total level of the award and the highly unusual steps of ordering the Prison Service to pay aggravated damages and legal costs, reflect the tribunal's view of the comprehensive failure on the part of the Prison Service.

"What makes this even more troubling is that the case bears striking similarities to the Lingard whistleblowing case. Despite assurances that the service would learn lessons from that case, it seems that it has done little to change the culture that encourages people to 'turn a blind eye' and victimises those who speak up."