Killer Hazel Stewart has top London lawyer

Brendan Kelly QC has been instructed in the challenge which is centred on any advice from her previous legal team at the time she abandoned the original appeal.

His high-profile previous clients include Mark Bridger, the man ultimately convicted of murdering Welsh schoolgirl April Jones.

Stewart, 52, is serving a minimum 18-year jail sentence for the killings of Trevor Buchanan, 32, and 31-year-old Lesley Howell, the wife of her ex-lover Colin Howell.Both victims were found in a fume-filled garage in Castlerock, Co Londonderry back in May 1991.

Police originally believed they had died in a suicide pact after discovering their partners were having an affair.

Although Howell, 56, eventually pleaded guilty to the killings in 2010 and implicated Stewart in the plot, she is pressing ahead with a second attempt to clear her name.

In January 2013 the Court of Appeal rejected her first challenge to being convicted of Lesley Howell’s murder. At the start of that hearing it was announced that the former Sunday School teacher would not be proceeding with the appeal against being found guilty of killing Constable Buchanan.

She claims, however, this was only done on the understanding that she could revive her case at a later stage.

Both Stewart and her second husband have filed court affidavits setting out their understanding of the circumstances.

Leading her case is Mr Kelly, who defended Bridger at his trial for the murder of five-year-old April Jones.

The schoolgirl went missing from outside her home in Machynlleth, Powys in October 2012. Her body has never been found.

In court on Friday Mr Kelly identified two points about the abandonment of Stewart’s original challenge to being convicted of murdering Constable Buchanan. He told three senior judges there was an issue about whether or not she was advised that amounted to a discontinuance of the challenge.

“The second point relates to whether or not she was advised that she had any grounds of appeal,” he added.

The barrister stressed that he was “treading particularly cautiously” in raising any alleged failings.

A full hearing of arguments on the circumstances surrounding the abandonment was listed for September. Lord Justice Girvan directed that before then Stewart should submit a further statement.

He said it should “set out clearly the averments she is seeking to put before the court to ground the basis of her complaint and allegation and justification for allowing the matter to proceed”. It was accepted by Mr Kelly that the case could not be classed as urgent.

He said: “The outcome of this appeal is not going to have any impact on the life sentence being served (for the other murder).”

Stewart’s lawyers are also separately seeking to have the Criminal Cases Review Commission refer her conviction for killing Lesley Howell back to the Court of Appeal.