The father of a two-year-old girl killed by her mother and the woman’s new boyfriend after what prosecutors described as a “sadistic” campaign of violence says authorities failed his daughter and missed opportunities to protect her.
Isabelle Welsh had suffered 21 broken bones in the weeks before she died at her mother’s home in Thornaby, Teesside. Her fatal injuries came after a final “massive head injury” was inflicted shortly before her death.
Her mother, Alexandra Walker, and Walker’s boyfriend, Harrison Simpson, were both found guilty of murder in July.
Simpson, 22, was also convicted of sexually assaulting the toddler, while Walker was cleared of that charge.
Both were sentenced to life in prison. Simpson must serve a minimum of 27 years and 231 days, while Walker, 26, was handed a minimum term of 21 years and 48 days.
Speaking in detail for the first time about Isabelle’s murder, her father, Joshua Welsh, 27, criticised the authorities – most notably the NHS and the police – for failing to keep Walker and Simpson away from the little girl.
In one incident, Walker left Isabelle in pain for two weeks with a fractured leg before seeking medical attention.
When she finally sought help – 11 days before Isabelle’s death on September 14 2025 – staff at North Tees Hospital in Stockton, Co Durham, did not want to allow Isabelle to return to Walker’s home, fearing potential abuse.
But when they raised safeguarding concerns, Walker became argumentative and threatened them.
Ultimately, staff on a paediatric team ‘overruled’ the concerns and she was allowed to go home.
Little Isabelle Welsh, two, was murdered by her mother, Alexandra Walker, and Harrison Simpson, who Walker had known only a matter of months
It later emerged Simpson was also the subject of an arrest warrant issued 18 months before the murder but police failed to locate him.
Mr Welsh said he only found out two days after the verdict about the outstanding arrest warrant.
‘I did not get told by the police,’ he said.
‘My sister found out about it on local radio. I was absolutely raging. I was angry, hurt and upset. The police should be ashamed of themselves.
‘If they had done their job properly Isabelle would still be alive today. I want to campaign and raise awareness – to make sure the police do proper checks to stop this happening again.
‘Instead of leaving innocent kids in the hands of monsters I want them to do their jobs properly.’
He added: ‘Social services needed to carry out welfare checks, the NHS child protection also let her down.
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‘Isabelle could have been saved in the NHS had worked properly. If the nurse was not overruled by clinical doctors who did not have a clue.
‘There are such wide ranging failures – from the police to the social services to the NHS.
‘There were several chances for the authorities to step in and save her. Yet she was handed back to these monsters. That is unforgiveable.
‘But I will remember Isabelle for her smile, for the happy and cheeky girl she was. Not by a photo of her next to those ugly monsters. As that is all they are.’
The court heard Walker had concerns about paedophile Simpson, who sexually assaulted Isabelle shortly before her murder, but continued to see him
Walker, of Thornaby, Teesside, was jailed for life with a minimum term of 21 years and 48 days in prison
Mr Welsh said he split from Walker in August 2024 following a five-year relationship but had not seen his daughter for some months before her death.
He said he had had no welfare concerns for Isabelle despite not being able to see her as much as he wanted and had never heard of Simpson until his arrest.
The court also heard that there were no concerns about Isabelle’s welfare until she began a relationship with Simpson, who she met on Facebook Dating.
She grew suspicious of Simpson’s interactions with her daughter and even checked the Sex Offenders’ Register to see whether he was a paedophile, but did not break up with him.
Mr Welsh added: ‘I had a very close bond with Isabelle. I was the first to hold her when she was born.
‘I would always get a special cuddle from her and she was my little angel.
‘I did not have a clue about her new boyfriend. I did not know him from Adam.
‘I had no suspicions of her while we were together. I did not in any way think she was capable of something like this.
‘I thought she was a good mum. I think it’s all his influence to tell you the truth.
‘I am trying to get more information on it. But I knew nothing at the time.’
In relation to the outstanding warrant, Cleveland Police said in a statement: ‘Multiple inquiries and arrest attempts were carried out to try to locate and arrest him, but these proved unsuccessful.
‘We recognise the time Simpson had an outstanding arrest warrant is far from adequate. A review of this was immediately conducted upon his arrest for murder.’