News emerges as part of watchdog report saying force is failing in way it handles racism complaints against officers from public

Six Metropolitan police officers are facing the sack for sending each other racist jokes, it has emerged on the day that the police watchdog said the force was letting down the public in the way it handled racist complaints.

The officers, from the borough of Kensington and Chelsea in west London, are alleged to have sent a total of 31 text messages described as being of a "highly offensive nature" in the summer of 2012.

They are due to face a gross misconduct hearing in November, where the maximum sanction is dismissal without notice if they are found guilty of the discreditable conduct alleged.

Of the six officers, one is a sergeant with nine years service and five are constables. Two of the six, the sergeant and a PC, have been suspended, while the rest are now on restricted duties.

Eight other officers were sent messages, one of whom reported the offensive nature of the texts to his bosses in July 2012. Those eight officers have been dealt with by management action, such as words of advice.

The case is being investigated by the Met's directorate of professional standards, which believe the texts were sent when the officers were off-duty. The incident was not made public by the Met. Instead it is contained in a report released by the police watchdog, finding the Met is failing in the way it handles complaints of racism against officers, over a decade after the force vowed to stamp out prejudice in the ranks.

The report by the Independent Police Complaints Commission led the Met to admit it was letting down the public in the way it handled racism complaints.

The report followed allegations of police racism in 2012 in a series of incidents, some of which were revealed by the Guardian. Those allegations led to IPCC to investigate.

The IPCC said it was "crucial to public confidence" that racism complaints were handled fairly.

It found that 511 racism complaints were made against officers in April 2011 to May 2012. In some the Met investigation comprised of asking the officers to respond by email, than accepting their denial and finding against the complainant.

The watchdog also found the Met issued a "standard, generic apology" regardless of what the investigation found which of "very little value".

IPCC commissioner Jennifer Izekor said: "This report shows that, though there are some examples of good practice, in general there is an unwillingness or inability to deal with these complaints robustly and effectively.

"Too often, complaints are dismissed without proper investigation or resolution, complainants are not properly engaged with, and lessons are not learned."

The IPCC report is the latest dent to the Met's claims to have done all it can to clean up racism. It has recently faced criticism over stop and search, and to have attempted to smear the family of Stephen Lawrence, murdered in a racist attack, whose killers were left free in part because of institutional racism, according to the 1999 Macpherson report.

Izekor said: "We know that there is less confidence both in policing and in the complaints system among BME [black and minority ethnic] communities. If the Metropolitan police service is serious about building that confidence, there will need to be a cultural change to complaints handling."

The IPCC called for "a cultural change in the way the MPS deals with such complaints, supported by training, monitoring and community feedback".

The IPCC paid special attention to 20 cases where the Met was left to investigate racism cases itself. It found in the majority, 13 cases, "the investigating officer made no effort to obtain additional evidence that could have supported the allegation of racism".

In its response, the Met vowed to reform and learn. The assistant commissioner, Simon Byrne welcomed the report's critical findings and said: "It is powerful, showing the way we deal with complaints involving racism is letting down the public."

He added the force was determined to "be less defensive and accept when we are not performing as well as we should be".

Byrne said the force favoured an independent ethics panel to oversee misconduct proceedings for the Met, and wanted senior officers to meet those who felt let down to humanise complainants and improve their negative experiences of complaining about police racism.