The murder of a two-year-old was “gross, cruel, brutal, catastrophic and totally devoid of humanity”, a judge at Belfast Crown Court was told as he considered how long her killer and her mother must spend in jail.

Ali Jayden Doyle died from head injuries she suffered at a house in Park Avenue in Dungannon in August 2021.

Ali Jayden’s mother Jade Dempsey admitted child cruelty and is yet to be sentenced.

Dempsey’s on-off boyfriend at the time, 35-year-old Darryn John Armstrong, admitted the toddler’s murder and was handed an automatic life sentence, but the minimum number of years he must serve before applying for parole has not yet been set.

A tariff hearing was held at Belfast Crown Court on Thursday where both prosecution and defence barristers read final submissions.

The court heard Ali Jayden died from a catastrophic head injury including a fractured skull.

Armstrong, whose address was given as HMP Maghaberry, initially blamed Ali Jayden’s one-year-old brother for causing the fatal wound by throwing a toy at her, causing her to fall back and hit her head on a fireplace.

A prosecution barrister said Armstrong later changed his story during separate police interviews and said he threw the child and she hit her head on the fireplace.

He said he had been under the influence of drugs and his dogs had run into the house and startled the children.

The barrister said the killer changed his story again and said he had no recollection of what happened, but admitted responsibility.

The court heard that according to a report from a pathologist, the severe injuries sustained were the result of blunt force.

A report from a doctor in neurosurgery said they “could envision a scenario where the child was grabbed by its torso and slammed down…with a serious degree of force”.

The barrister said due to the severity of the injuries sustained: “There couldn’t have been any other intention but to kill in this case”.

The court heard that on the day of the murder, Dempsey left her children in Armstrong’s care while she left to go to Belfast to buy a pram.

Shortly afterwards she received a WhatsApp video from Armstrong, showing Ali Jayden sitting watching TV.

But about 15 minutes later while waiting at the bus station, Dempsey was called to return home.

The prosecution barrister outlined how the ambulance service arrived to Ali Jayden unconscious, laying on the bedroom floor.

Her hair was wet and a towel was wrapped around her.

The prosecution barrister told the court that Armstrong had said the child was burning up and he was trying to revive her by putting water on her.

They also outlined how a neighbour described hearing “three screeches” coming from Armstrong’s home at about the time of the murder but that the noise then stopped.

The court heard that Dempsey’s children, including Ali Jayden, had been on the child protection register at the time of her death.

A protection order was also in place preventing Armstrong from being in contact with or near the children due to his criminal history.

He has 77 previous convictions including domestic violence offences.

Armstrong was also on probation for domestic violence offences.

Judge Mr Justice McAlinden said the pair had taken a “deliberate decision” to ignore the protection plan in place by social services.

He added that he wanted to send a message out to others in similar situations that “there will be consequences to those that breach them”.

A defence barrister for Armstrong said he was not in disagreement with the prosecution and that they accepted the defendant was responsible.

“At the centre of this case is a young child that suffered a catastrophic fracture which was the result of a high impact blow caused by the defendant”, the defence barrister said.

He also outlined how Armstrong came from a “remarkably dysfunctional” background, growing up in care and being exposed to domestic violence and guardians with drug and alcohol addictions.

The defence barrister said Armstrong’s drug use resulted in him “losing control” on the day that Ali Jayden was murdered.

After submissions were made by the prosecution and defence, Mr Justice McAlinden said he needed time to reflect on what he heard and would sentence Dempsey and set a minimum tariff for Dempsey at a later date.