Social workers and health professionals met 24 times in four years to discuss concerns over the possible sexual abuse of two children who they failed to protect - even after discovering one toddler was suffering from genital warts.

The harrowing home life of the brother and sister was laid out in a serious case review published yesterday - as it is revealed Cumbria County Council chiefs are now preparing for a crunch Ofsted inspection of the authority's children's services department before Christmas.

An apology over mistakes in the case has now been issued by Cumbria's children's services boss Councillor Anne Burns, who added an assurance that significant improvements have been achieved since the authority's last failed Ofsted inspection to make sure Cumbria's most vulnerable children are safe.

"This was a complicated case, but it is clear from the report that it took too long for the children to receive the right protection," Cllr Burns said.

"That was not good enough and we’re sorry for that.

"We are now working closely with the LSCB and other partners to ensure the LSCB action plan is implemented and that all professionals working with children understand the lessons from this case."

A team of inspectors from Ofsted are expected to descend upon CCC's children's services department imminently to review its operational standards.

It has been judged as inadequate following its last three successive inspections. Since 2015 the authority has been the subject of a stringent review regime with ministerial oversight by the Department for Education as well as a peer review process by experts from other local authorities.

Cllr Burns added: "These events occurred between 2009 and 2013 at a time when shildren’s services was judged to be inadequate.

"We have been working hard since then to improve the quality and consistency of our support and protection for children and families.

"In the last two years we have been subject to rigorous monitoring by OfSTED and the DfE to assure them that services are improving, this has included 14 OfSTED monitoring visits and three Department for Education reviews.

"While challenges remain, these reviews have consistently shown that progress is being made and services are improving.

"We are anticipating a full OfSTED inspection before Christmas and I am confident this will conclude that our services to children have improved."

The serious case review charts an appalling catalogue of missed opportunities by social workers and health professionals to safeguard the children, now aged eight and ten.

It illustrates how the youngsters, who are not identified for legal reasons, were left to live with various family members amid a 'chaotic' background of multi-generational sexual abuse, domestic violence, alcoholism and drug taking until they were eventually taken into care in 2013 aged four and six.

Social services were aware of the desperate circumstances surrounding the children - holding a total of 24 meetings about their welfare and making them subject to two separate child protection plans between 2009 and 2013.

But no decisive action was taken to safeguard either of the toddlers despite a range of serious incidents concerning both siblings.

These included referring the little girl to a medical expert after she began exhibiting 'sexualised behaviour' at nursery. She was found to have bruises on her thighs and genital warts, though doctors could not categorically confirm they were the result of sexual abuse.

On one occasion, the pre-schooler was taken to A&E after taking a substance her mother had bought 'on the street' to help with her withdrawal from other drugs.

Health professionals, including a GP, noticed her younger brother with a number of injuries including a cut and a bruise over his eye.

Social services were also notified when he was smacked so hard by a family member he was left with a hand print on his skin and after he suffered a broken leg in an accident reported to have occurred on a see-saw.

Independent child welfare expert Saffron Rose, author of the serious case review, said: "This is a case that was characterised by chronic and extreme neglect within a highly dysfunctional family system.

"All of the adults had serious emotional and/or physical ill health issues that made it practically impossible for them to prioritise and safeguard the children."

She added: "At the second review case conference it was troubling that the registration category changed to neglect and the focus on sexual abuse slipped off the radar and no further assessment was progressed in relation to this.

"Had further assessments been pursued, information may have been obtained that should have led to earlier interventions to effectively protect the children."

Cumbria's children's services department: A timeline of failure

April 2012: Ofsted inspectors rate the department as inadequate and order it to improve.

May 2013: Inspectors return to check progress but issue a further inadequate rating to the authority.

May 2015: CCC is branded inadequate for the third time in four years in successive Ofsted inspections sparking leaving uncertainty over whether the council will retain control of its own children's services department.

January 2017: An interim monitoring visit concludes improvements are taking place, but that the standard of practice across Cumbria remains inconsistent.

Imminent: Ofsted inspectors are set to carry out a full, formal inspection before Christmas. The authority must secure at least 'requires improvement' - one rung up from 'inadequate' - if it is to run the department in future.

Cumbria's serious case reviews

Serious case reviews are carried out when a child has died or been harmed and abuse or neglect is thought to have been a factor.

They are completed by an independent third party to identify the circumstances surrounding the death - and what can be done to learn from each tragedy.

The reviews are then published by Cumbria's Local Safeguarding Children Board.

Serious case reviews published by the LSCB in the last two years have included:

:: Child AC, published June 2016.

Jordan Watson, 14, from Carlisle, who was known to social services, was murdered in a premeditated attack by three men in the city in July 2015.

The review made a series of recommendations to improve communication between agencies but concluded the teenager's death was entirely unforeseen.

:: Child N, published June 2016.

Poppi Worthington died in suspicious circumstances at her home in Barrow in December 2012, aged 13 months.

The review found health and social care agencies missed the signs that Poppi was at an increased risk because of a history of abuse in her family.

It concluded her family should have been offered additional support.

:: Child R, published July 2016.

Kye Backhouse was a 14-year-old boy from Barrow who died after taking a morphine tablet given to him by his father.

The review found his death could not have been predicted nor prevented.