A "troubled" police force heavily criticised after the death of a 13-month-old girl needs "immediate" improvement in order to protect children, watchdogs have said.
The 41-page report by Her Majesty's Inspectorate of Constabulary (HMIC) lists a catalogue of poor practice by Cumbria Police, following their inspection and checking of child protection case files.
Local MP John Woodcock, who represents Barrow and Furness, said Cumbria Police needs "rapid improvement" to ensure the "horrific abuse" of youngsters is identified and those responsible punished.
The HMIC report comes in the wake of the notorious case of Poppi Worthington, the toddler whose death in 2012 is still the subject of multiple investigations.
A judge in the family courts ruled that Poppi's father, Paul Worthington, probably sexually assaulted Poppi before her sudden death at home in Barrow on December 12 2012.
However, the police failed to carry out a proper investigation, evidence was lost and no one has ever been charged over the youngster's death.
Her father was originally arrested on suspicion of sexual assault in August 2013 but no action was taken against him, and he has always denied any wrongdoing.
Cumbria Police later apologised and said lessons had been learned.
However, today's HMIC report highlights serious failings in the way the police continue to deal with child protection cases and suggests a number of urgent improvements needed.
A number of case studies in the report identify "shocking" cases where procedures have not been followed, leads have not been pursued and children's safety has potentially been put at risk, the MP said.
The cases include the mother of a girl, 14, disclosing that her daughter had been in a sexual relationship with a number of men, including a 19-year-old registered sex offender.
The suspect was arrested and the matter investigated, but inspectors found no evidence of a longer-term safeguarding plan to protect the girl from further exploitation and nor was there evidence that any consideration was given to identifying the other males with whom the girl was having sex, with a view to establishing whether other offences or victims existed.
In another case an eight-year-old girl alleged she had been sexually assaulted by her mother's partner.
But the suspect was not arrested for three weeks following the initial report and the suspect was not considered as a possible serial offender for six months, despite being known to have access to other children and explicit images of other children being discovered on his phone.
Mr Woodcock said: "Parents across the county will be alarmed by the report's chilling examples of child sex victims who were not given proper protection from Cumbria police.
"Similarly disturbing are the instances where there is no record of suspects of serious sexual offences being properly investigated.
"The report did contain some examples of good practice and it is encouraging that Her Majesty's Inspectorate concluded Cumbria's police officers are clearly committed to protecting children and determined to turn the situation around.
"But the multiple failures outlined by the HMIC are stark and point to horrible abuse going undetected and offenders going unpunished.
"Rapid improvement is essential to safeguard our community - this already troubled police force must be placed under even greater scrutiny until these problems are fixed."
No one from Cumbria Police was available for comment.