“Fresh evidence” suggests that double murderer Hazel Stewart was suffering from mental illness when she killed her policeman husband and the wife of her ex-lover, Colin Howell, a court has heard.
The Court of Appeal in Belfast also heard submissions that Stewart, 62, a former Sunday school teacher, was being coercively controlled by Howell at the time of the killings in 1991.
Three appeal court judges are hearing an application that Stewart should be given leave to mount an appeal over the length of her sentence.
However, a barrister for the Public Prosecution Service said that, more than 30 years after the murders, Stewart had “finally found a doctor who will say something sympathetic”.
Stewart is serving a minimum 18 years behind bars for the killing of Constable Trevor Buchanan, 32, and Howell’s 31-year-old wife Lesley Howell.
Both were found in a fume-filled garage in Castlerock, Co Londonderry, in May 1991.
Police originally believed they had died in a suicide pact, after discovering that their partners were having an extra-marital affair.
Instead, they had been drugged and murdered and their bodies arranged to make it look as though they had taken their own lives.
Nearly two decades passed before dentist Howell, 65, confessed to both killings.
He implicated Stewart and she was ordered to serve at least 18 years, at her trial in 2011.
She is making a fresh bid to have her sentence reduced.
Stewart, wearing a blue T-shirt and a necklace with a cross, watched proceedings via video link from Hydebank Prison.
Lesley Howell’s daughter, Dr Lauren Bradford-Clarke, was in the court, as was Stewart’s second husband, David Stewart.
The court heard lengthy submissions on whether it has jurisdiction to order a new appeal.
It also has to adjudicate on a preliminary point about delay in raising the fresh ground of appeal.
Representing Stewart, Brendan Kelly KC said: “This application was created by the discovery of fresh evidence.”
He said a series of reports from a psychiatrist in 2024 had said Stewart was “suffering from two forms of mental health, depression and PTSD” at the time of the murders.
He said “coupled with coercive behaviour” from Howell, these were factors that should have been taken into account during her sentencing.
The barrister said the new evidence was “cogent and admissible”.
He said her mental illness had been caused after she had an abortion in 1990, adding that her condition “simply wasn’t identified or recognised” at the time of her trial.
Pointing out that the diagnosis had been made only last year, Mr Kelly said “it was difficult to see how we could have moved more quickly”.
The barrister said the application to give leave for appeal should be granted, the new evidence submitted to the court and the psychiatrist called as a witness.
Representing the Public Prosecution Service, Philip Henry KC said Stewart’s barrister was trying to create an “exceptional scenario”.
He said the appeal judges were being invited to “feel so uncomfortable” about the new medical evidence that a “sense of injustice is provoked”.
He said the psychiatrist was first instructed in 2023 and was initially given some, but not all, of the relevant medical material.
Mr Henry said: “What we have here is a psychiatrist, 30 years after the event, diagnosing depression and PTSD.”
The barrister said there had been six medical reports on Stewart closer to the time, adding “every single one of those doctors examined the applicant in person”.
He said none of them had concluded there was evidence of mental illness.
He added: “We have six reports, all closer to the time, all doctors properly instructed, all examined the applicant and none of them had concerns about mental illness at the time of the offending.”
The barrister then referred to emails from Stewart’s husband, David Stewart, to her solicitor, in which Mr Stewart had said medical experts were attempting to find evidence of mental illness but would not be able to.
Mr Henry said: “Finally a doctor has been found who will say something sympathetic.”
The barrister said the recent psychiatric report was in “direct contravention” of all previous medical evidence, describing it as “one solitary voice”.
He said that after the new psychiatric report, the court was “nowhere near” the point where it could allow an appeal over the sentence to proceed.
Mr Kelly denied that Stewart’s legal team had been “shopping for a psychiatrist”.
Lady Chief Justice Dame Siobhan Keegan said the court would rule on the application next month.
Following the hearing, Dr Bradford-Clarke was hugged by a number of supporters and friends outside court.
