A series of agencies failed to spot signs which might have prevented a couple leaving their five children to starve in squalor, a report has found.
David Askew and Sarah Whittaker, both 24, were jailed for seven years each in 2004 after admitting child cruelty.
Police found critically ill one-year-old twins, one "within hours of death", at their home in Sheffield.
The report by senior civil servant Prof Pat Cantrill said not one single agency had looked at the family as a whole.
Officers called to the family home found the twins and three other children - aged three, four and seven - living in squalid conditions in excrement-smeared bedrooms.
Meanwhile, Askew and Whittaker apparently lived a life of comfort downstairs surrounded by state-of-the-art electrical appliances.
Prof Cantrill, a former assistant chief nursing officer at the Department of Health, was commissioned by the Sheffield Area Child Protection Committee to conduct a "serious case review" after the convictions.
Her report, published on Wednesday, said the family were not known to the child protection authorities, despite a number of opportunities for education and health workers to have spotted tell-tale signs of problems.
She said one of the most important underlying problems was the failure of teachers and health workers to mark out any of the children's problems as exceptional, because of low expectations in their community.
Police were shocked at the state of the house
The twins were premature and spent time in a special care unit, but Askew and Whittaker failed to attend neonatal appointments after discharge.
Midwives and health visitors saw the twins on six occasions at home, but did not report any severe problems.
A health visitor called, but did not see the babies and did not raise an alarm.
Police called to a domestic violence incident did not check on the children.
Area Child Protection Committee chairman Alan Jones said local services had already started to implement all the report's recommendations.
"This has been an extremely distressing case for the whole of the childcare community in Sheffield," he said.
"We recognise that every professional working with children in the city needs to have the same core skills and knowledge to be able to recognise and respond appropriately to children at risk of significant harm.
"However, professionals can only intervene to protect children if they are made aware that there is a risk of abuse or neglect.
"We encourage members of the public to talk to us if they have any concerns about the safety of a child."
Paramedics and police were called to the family's home in June last year after Whittaker phoned for an ambulance because one of the twins was "lifeless".
The conditions officers found were so appalling some said they found it difficult not to be sick.
In her report, Prof Cantrill said: "We could so easily have been reviewing the fatality of a child rather than the neglect, and therefore it is important that the role of the services involved with the family is closely examined."
She said agencies involved with the family had failed to detect and intervene early to prevent poor parenting.
Household rubbish was strewn across the filthy kitchen
It was "unacceptable" that professionals working in deprived areas should have a higher "threshold" before action was taken because of the general background of problems in the community.
She said this was most evident within the primary care, maternity and education services in Sheffield.
"No child should have to experience such a level of neglect before services become sufficiently concerned to assess their need for support."
A Sheffield City Council spokeswoman said the children were now with foster families.
The twins were together and the other three children were with different families, but the children all had regular contact together.