An evil mother and her half-brother have been jailed for life for murdering their two sons and trying to kill four other children they had through an incestuous relationship.

Sarah Barrass and her half-brother Brandon Machin had six children together but tried to kill them all rather than hand the youngsters over to the care system.

The couple’s two eldest sons Blake, 14 and Tristan, 13, were found lying fatally injured on their bunk beds at home in Sheffield when police arrived in May.

They had been strangled and suffocated by Barrass and Machin, while others had been drugged and held under water in the bath, in an apparent effort to stop them being taken into care.

After full details of the shocking case were outlined in court today, Barrass, 35, and Machin, 39, were both jailed for life and ordered to serve at least 35 years behind bars.

The siblings, who are related through their mother, will be in their seventies before they can apply for parole.

One of the surviving children told social workers they were ‘worried they would become a murderer when they were older because that is what his mum and Brandon did’ and added that they wanted their parents to go to jail for ‘300 years’.

The court heard two killers had come from a dysfunctional family and Machin had himself been taken into care when he was 14.

The pair embarked on a sexual relationship when he came out of care and they met up.

Social services had been involved with their family in the 1990s and concerns had been raised about the half-siblings developing a sexual relationship.

The children believed and told officers at the scene their father was dead, having died in the Second World War.

Kama Molly, prosecuting, told the court: ‘The six children lived alone with their mother Sarah Barrass. The picture of the Sarah Barrass household prior to the events in 2019 was, to the outside world, a household of a loving single mum with six children, heavily supported by her brother Brandon Machin.

‘In fact, unbeknown to everyone but the defendants, Brandon Machin was in a sexual relationship with his half-sister, Sarah Barrass and he was the father of all six children.

‘The children believed and even told officers at the scene that their father was dead, having died in the Second World War.’

Today’s revelations will add to questions from Barrass’s family about why more wasn’t done to protect the children sooner.

The court heard they hatched their plot to kill the children because Tristan had been accused of sexually assaulting a younger child and Barrass feared it would lead to all the children being taken from her.

In May this year, they grabbed Blake and Tristan, with Machin strangling Blake whilst Barrass strangled Tristan, using a dressing gown cord.

The pair then swapped victims and placed black bin liners over their heads ‘to make sure.’

ADHD medication used by the children had been gathered up from around the ‘unkempt’ home that Barrass shared with her six children. She then portioned out the medication to the youngest children, who are all aged under 13.