According to an official report, the Metropolitan Police Department is riddled with deep-seated racism, sexism, and homophobia and has failed to change despite numerous official reviews urging it to do so.

Louise Casey’s report, which is set to be released on Tuesday, will be critical of Britain’s largest police force.

Senior government and law enforcement officials are aware of its contents, which have been described as “horrible” and “atrocious” by one. One source with knowledge of the findings said the report would make clear that the Met was in the “last-chance saloon”.

Following the murder of Sarah Everard by a serving Met officer, Wayne Couzens, in 2021, the force commissioned the report. The report will look into whether Met failures are caused in part by institutional misogyny, homophobia, and racism.

Lady Casey will condemn the force for failing to address its problems despite decades of warnings in previous official reports, and she will back up her claims with damning new case studies.

In 1999, Sir William Macpherson’s report on the failings that allowed Stephen Lawrence’s racist killers to escape justice for so long identified institutional racism as a cause of some of the problems. The Met announced a decade later that the label no longer applied. Casey, on the other hand, will say that significant problems remain, and she will ask what should happen to the Met if it cannot reform.

According to Whitehall sources, the final draught has been sent to the Met leadership and government, prompting crisis talks in recent days between Sir Mark Rowley, the Met commissioner since September, and the home secretary, Suella Braverman.

The Met’s most recent disasters, such as the cases of Couzens and serial rapist David Carrick, were not isolated incidents, but rather symptomatic of how profound and serious its failings had become, according to the report. It will criticise previous poor leadership and claim that pernicious cultures took root and grew in the Met.

Couzens and Carrick were both found to be fit to carry a gun and served in the same unit, the parliamentary and diplomatic protection command, which Casey will point out has an unacceptable level of problematic behaviour.

Former Met leaders, including Cressida Dick, have received so-called Maxwell letters, which allow figures criticised in an official report to respond before publication.

The 300-page report is expected to criticise Dick’s leadership as the Met’s problems grew from 2017 to 2022. However, it will state that the issues were evident prior to her appointment as commissioner. One Dick supporter stated that during her tenure, she was focused on reducing violent crime.

Casey will argue that austerity, which began in 2010 when the Conservative government cut police budgets, harmed the Met, its neighbourhood policing, and its relationships with the communities it serves. Overworked officers and units have been identified.

The outpouring of rage in the Couzens case after he was sentenced to life in prison prompted Dick to order the review in October 2021. Dick was fired as commissioner in February 2022 because London mayor Sadiq Khan did not believe she could lead the Met out of its crisis.

According to the Casey report, while Couzens and Carrick were responsible for their crimes, warning signs about the dangers they posed were repeatedly overlooked. Couzens was a serial flasher, but despite his crimes being reported to the Met, the Met failed to identify him as a threat to women.

A draught of the Casey report has been sent to Rowley, who is said to be shocked by its findings and concerned about the further damage it may do to public trust in the Met. Before Carrick’s conviction in January and details of the Met errors that allowed him to attack women, confidence was already low.

According to one senior source, Rowley’s turnaround plan had a year to show signs of success. Another stated that the commissioner had two years to demonstrate progress.

Casey’s first set of findings, released in October 2022, focused on the Met’s disciplinary system and discovered that far too many complaints from officers and staff about their colleagues were dismissed. Rowley has promised reforms and has vowed to change that.

According to the October report, officers and staff were being fobbed off when they complained of wrongdoing, and they were hesitant to do so because they feared nothing would be done or that they would face retaliation.

It discovered that officers suspected of serious criminal offences, such as sexual assault and domestic abuse, had been allowed to evade prosecution, and Rowley admitted that hundreds of racist, women-hating, and corrupt officers had remained on the force.

The Met was placed in special measures by the policing inspectorate last June due to a series of failings.

The review into the culture and standards of the Metropolitan police was commissioned in light of the appalling facts relating to the murderer of Sarah Everard,” a Casey review spokesperson said.

“This must be remembered if at all possible as we move towards its publication. We will not make any comments on its content before it is published. We respectfully request that others do the same.”

The government has commissioned two more official reports on policing, including one on the Couzens case, which will be released this year.

The Met is facing another damning report on the failings that allowed serial killer Stephen Port to walk free, and the police watchdog will announce this month whether a Met firearms officer should be referred to prosecutors in connection with the shooting of Chris Kaba last September.

Kaba’s relatives expressed “concern” about the resignations of two officials from the watchdog investigating the shooting on Thursday night.

We are concerned that two senior members of the IOPC [Independent Office for Police Conduct] who have been overseeing the homicide investigation in this case, Michael Lockwood and Sal Naseem, have resigned during the investigation,” the family said.

We find this unsettling and are concerned that it has no bearing on the nature or timing of the IOPC decisions – we have already waited far too long to learn whether the IOPC is seeking CPS advice on criminal charges.

Lockwood, the IOPC’s director general, resigned in December because he was the subject of a police investigation into a historical allegation.

Naseem, the regional director for London and national lead for race discrimination, announced his departure this month, according to the organisation.