The Metropolitan police is deleting findings of discrimination within the force to preserve its reputation, a damning tribunal ruling has found.
The policy emerged during the employment tribunal of Carol Howard, a 25-year-old firearms officer in the Diplomatic Protection Group who brought a claim of discrimination earlier this year.
"My client was subjected to discriminatory treatment because she is black and because she is a woman," her lawyer, Kiran Daurka, from Slater & Gordon, said.
"Fifteen years after the Met was branded 'institutionally racist' they have failed in addressing discrimination which pervades the system."
The tribunal found the desk sergeant tasked with evaluating Howard's fairness at work complaint was asked to delete references to discrimination or harassment relating to sex or race.
It found this action was taken specifically to cover up the record because she had gone to the tribunal.
The tribunal found the practice of deleting references amounted to a "policy" and that it was "very concerned" the Met was trying to "mislead complainants and tribunals into believing that the [investigating officer] has not found any discrimination when in fact he or she has done so".
Daurka told the Today programme: "We anticipate that wherever there's findings of discrimination, they're being instructed to delete them.
"They've admitted that they do this practice... so that there are no findings of discrimination against them."
Daphne Romney QC added: "What is particularly shocking is the deliberate attempt to cover up internal findings of discrimination.
"The outcome of the internal grievance investigation led PC Howard to believe that the investigating officer did not accept that there had been either race or sex discrimination, when clearly this was not the case."
London Mayor Boris Johnson said he was "dismayed" by the tribunal ruling and pledged to look into the previous 34 tribunals on discrimination at the Met.
"I am concerned about this particular case, I'm concerned about the tribunal's findings and I certainly want to get to the bottom of it," he said.
"I'll certainly be taking it up with police to make sure all the comment of the tribunal which raise serious concerns are properly addressed."
The tribunal found in favour of Howard and said she had been "singled out and targeted" between January 31st and October 29th 2012.
The Met had "directly discriminated" against Howard "on the grounds of sex and race".
Her superior, acting inspector Dave Kelly, quickly "formed the view... that the claimant was dishonest and not up to the standard required" even though he had not provided a "credible basis for forming such a view".
The Met said: "We are disappointed at the tribunal's finding in favour of PC Howard.
"We will review the findings, take legal advice and take forward any learning or actions as appropriate."
Metropolitan Police Federation chairman John Tully, who supported Howard, said: "Whilst we are pleased that this judgment recognises that racist and sexist behaviour is unacceptable and is capable of being challenged, it is of concern that such issues are still prevalent in the Metropolitan police service, despite the many measures introduced to address the problem."