During the short life and slow, brutal death of Baby P, staff at Haringey's social services department who had responsibility for protecting him were twice commended for the quality of the service they provided.

In two reports, published shortly before the abuse of Baby P began in November 2006 and three months after he was found dead in his blood-spattered cot in August 2007, inspectors from Ofsted praised the child protection service provided by Haringey and awarded the department three stars, the top accolade. When a whistleblower tried to alert the inspectorate and the Government to inadequacies in the handling of child abuse cases by the council, her warnings were dismissed.

In February 2007, as the attacks on Baby P were increasing, the former Haringey social worker Nevres Kemal sent seven letters via her solicitor to government departments and the Commission for Social Care Inspection, based on her experience on a separate case, demanding a public inquiry.

The commission had a meeting with Haringey but nothing was done. The abuse continued, although Baby P had been recognised as a child at risk, placed on the child-protection register and a police investigation had begun. The saga highlights the failure of the regulator, the failure of Haringey social services department, and the complicated bureaucracy in which not even the professionals know who has responsibility for what.

Ms Kemal's letter to Patricia Hewitt, then Secretary of State at the Department of Health, was forwarded to the Department for Children, Schools and Families, which had taken over responsibility for children's services. It, in turn, passed it to the Commission for Social Care Inspection, whose role as regulator of child protection services ended in April 2007 and was taken over by Ofsted. Details of the complaint remain shrouded in secrecy; Ms Kemal is subject to an injunction preventing her from speaking publicly.

After Baby P's death in August 2007, a post mortem examination showed he had a broken back, eight broken ribs, severe cuts and bruises and abrasions to his head, face and fingers. Now the same agency, Ofsted, that commended Haringey's children's services in 2006 and 2007 which failed to protect him, is to lead an inquiry into what went wrong.

Just a month before the abuse of Baby P began in November 2006, when his mother's boyfriend, who was obsessed with knives and Nazi memorabilia and had a fascination with inflicting pain, had moved into the family home, inspectors from Ofsted had given Haringey a clean bill of health.

Their report in October 2006, described the borough's child protection work as "generally of a satisfactory standard" which had shown "sustained improvements in practice and management" since 2001. It went on: "All children on the child protection register have an allocated social worker and cases are reviewed within timescales. Staff are well-managed and supported to carry out their roles and improvement in the quality of social work practice has been recognised by the local courts. General and specialist child protection training ... is very good, is valued by staff and improves the quality of child protection work."

The Joint Area Review by Ofsted and the Commission for Social Care inspection, the bodies responsible for regulating children's services in England, highlighted concerns about high staff turnover and difficulties in recruitment leading to delays and lack of continuity. But the overall tone was positive, especially for an authority still recovering from the nightmare of Victoria Climbié, the eight-year-old girl a few streets from Baby P who died in horrific circumstances in 2000 in a case that shook child protection work to its foundations.

Yet the Haringey department was unable to prevent the abuse of Baby P in late 2006 and through 2007, despite the efforts of social workers, doctors, health visitors and police charged with protecting him who saw the family on 60 occasions over eight months.

Weeks after he was found dead, inspectors delivered a second report on Haringey which was even more glowing. The annual performance assessment of services for children and young people by Ofsted, published on 26 November 2007, awarded the department three stars for its overall performance. It commended the reduction in the number of children on the protection register and said "thorough quality assurance systems are in place". It mentioned a "good partnership with the Metropolitan Police" and said the Local Safeguarding Children Board, responsible for child protection, had demonstrated "good ownership of the broader, safeguarding agenda".

This report led Sharon Shoesmith, 55, director of children and young people's services for Haringey, to mount a robust defence of her department at the end of the court case on Tuesday after the three perpetrators of the abuse were found guilty of causing or allowing the death of a child.

She twice refused to apologise for the borough's failure to protect Baby P. "This child was killed by members of his own family. The agencies are not responsible," she said, a claim seized on by critics who accused her of "breathtaking arrogance". Her colleague, Liz Santry, Haringey's cabinet member for children and young people, delivered the long-awaited apology from the council on Thursday. Ofsted, having twice praised the council's services for children, has been ordered by Ed Balls, the Secretary of State for Children and Schools, to lead a new inquiry. In a statement yesterday, it said it had known of the death of Baby P at the time of the November 2007 inspection, but the results of the local review of the case were not then available.

Ministers rejected claims that they had not acted on the separate warning from Ms Kemal, who won a racial discrimination case against the council in February 2007. Lawrence Davies, her solicitor, sent letters to ministers and government departments, and to the Commission for Social Care Inspection (CSCI) which had responsibility for children's services until it passed to Ofsted in April 2007. The Department for Children said it had "followed standard procedure" by directing the complainant to the inspectorate.

Mr Davies said: "The Social Care inspectorate are the people with the hit squads if they are tipped off about things like this. It is their job to investigate but they didn't. Why?" The CSCI said in response yesterday that it had discussed the allegations with Haringey Council but had not considered there was a need to investigate further.

Haringey: The regulator’s verdict

"Child protection work is generally of a satisfactory standard: most performance indicators are now in line with those in comparator authorities. This reflects good and sustained improvements in practice and management since 2001 when practice was poor... Staff are well managed and supported to carry out their roles... general and specialist child protection training for all relevant staff, including voluntary partners, is very good."

Ofsted report (Joint Area Review), October 2006, three years after Victoria Climbié inquiry and one month before abuse of Baby P began.

"The number of children on the child protection register continues to decrease and is now in line with statistical neighbours. Thorough quality assurance systems are in place ... all children on the child protection register have an allocated social worker and all reviews are held to timescale. The Local Safeguarding Children Board continues to demonstrate good ownership of the broader safeguarding agenda."

Ofsted report (annual performance assessment), November 2007, three months after Baby P's death, awarded the department three stars.

Baby P: A life cut short

1 March 2006

Baby P born. Parents split four months later

November 2006

Mother's new partner moves in – injuries begin

11 December 2006

Baby P admitted to hospital with two-inch bruise across forehead, and bruises to chest and shoulder. Doctors refer to social services

22 December 2006

Placed on Haringey child protection register. Mother and grandmother arrested on suspicion of assault and Baby P placed in care of Angela Godfrey, friend of his mother. Police investigation begins

26 January 2007

Investigation proves inconclusive and Baby P is returned to his mother, against the advice of police who said the investigation was not complete.

March-June 2007

Baby taken to hospital twice with bruises and injuries. In June, mother arrested again on suspicion of assault but later allowed to take her son home

July 2007

A lodger, Jason Owen moves in with the family. Police ask for multi-agency meeting on the case, but Haringey Council lawyers say there is not enough evidence to begin care proceedings

1 August 2007

Baby P taken to child development clinic at St Ann's hospital, where Dr Sabah Al-Zayyat failed to diagnose a broken back and broken ribs

3 August 2007

Baby P found dead in cot