Image copyright South Yorkshire Police

The murder of two children by their parents "could not have been predicted or anticipated", a report has found.

Sarah Barrass and her half-brother Brandon Machin strangled their sons Tristan and Blake Barrass, aged 13 and 14, in Sheffield, in May 2019.

The serious case review found Barrass was seen as a "loving, caring and competent" mother and the couple's actions could not have been foreseen.

Barrass and Machin were both jailed for at least 35 years in November.

The incestuous couple had admitted killing the two teenage boys and plotting to kill their four other children at their home in Shiregreen.

Their sentencing hearing was told Barrass and Machin had been in a secret sexual relationship for years and feared they would be found out and their children taken into care.

They hatched a plot to kill them, the court heard, intending for Machin to "discover" what had happened and raise the alarm.

The report, commissioned by Sheffield Children's Safeguarding Partnership, concluded there was "no evidence" to predict the events of 24 May 2019.

Author Alex Walters said: "It's a desperately sad and very tragic case involving the deaths of two children at the hands of their parents but, as the report has identified, there is no evidence that any practitioner could have predicted or anticipated the actions that were taken."

She said that throughout the 14 different agencies' involvement with the family, Barrass was seen as a "caring and competent" parent and rejected suggestions Barrass had "pulled the wool" over the authorities eyes.

"She was seen by all the practitioners as a capable and loving mother who advocated and fought hard for her children," Ms Walters said.

"This was a very busy household but throughout this time no concerns by any practitioner were raised around the quality of her care for her children."

Despite its assessment of how her parenting was viewed, the report states Barrass feared her children being taken into care, as she had been as a child.

At their sentencing, the court heard a day before murdering Tristan and Blake they had also forced the two teenagers, as well as two more of their children, to take tablets gathered from around the family home.

The court that Barrass and Machin expected the mixture, which included prescribed ADHD medication, to kill all four of them.

When that failed, they killed Tristan and Blake before trying to drown another child in the bath.

David Ashcroft, chair of Sheffield Children's Safeguarding Partnership, said the review had found "significant evidence of effective and caring practice for the children by all agencies involved with the family".

"However, as with any review, the process of reflection has identified some areas where the current systems and processes could be improved," he said.

Areas highlighted for review included improving the understanding of and response to harmful sexual behaviour; reinforcing the need to take a "holistic view" of a family's engagement with the authorities; and paying more attention to male carers.

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