Scotland Yard removed evidence of racial and sexual discrimination from documents it submitted to an employment tribunal, which has decided the force had "singled out and targeted" a black officer because of her race and gender.

The tribunal in London upheld complaints by PC Carol Howard that she had been discriminated against and also said it was "very concerned" by the conduct of the Metropolitan police.

Howard, 35, had been in the force for 10 years, serving as an armed member of the Diplomatic Protection Group (DPG), and had previously been selected by the Met to appear in a newspaper feature ahead of the London 2012 Olympics.

The tribunal ruled she had been "singled out and targeted" for almost a year by one boss, Acting Insp Dave Kelly, because of her race and gender. Kelly "ordered" junior officers to ask Howard about her sex life and whether she was sleeping with a colleague, it found.

Once Howard formally complained, a Met manager named David Jones asked the author of an internal report into the row to "delete all references to discrimination and harassment related to sex and/or race". The original version of the report, finding Howard suffered discrimination, only surfaced after her lawyers pressed for it.

The tribunal also ruled that the decision to remove the material damaging to the Met's denial of discrimination against Howard was a "policy" – and thus not down to a rogue manager. The tribunal judgment says the Met had done it before in previous cases.

Howard's solicitor, Kiran Daurka from Slater & Gordon, called for a public inquiry into how the force handles race discrimination claims. She also said Howard wanted to continue as a police officer.

The case comes at a perilous time for the Met's and the police's reputations after a series of scandals and controversies which led home secretary Theresa May to call for reform in a speech to the Police Federation in May.

The Met is facing a public inquiry over undercover officers spying on the family of Stephen Lawrence, ministerial pressure over excess stop and searches damaging black Britons' confidence in the police and concerns over the handling of rape and domestic violence cases.

It is still repairing the damage of the Plebgate affair following a verbal clash in Downing Street between former cabinet minister Andrew Mitchell and a police officer.

A number of Howard's complaints of victimisation were "well-founded", the tribunal said. It concluded that Kelly subjected her to "a course of conduct which was detrimental to her". The panel found that Det Sgt Fiona Hepworth, appointed to deal with the complaint, was asked to delete all references to sex or race discrimination in a report.

The tribunal judgment said: "We found that DS Hepworth was asked to delete all references to discrimination and harassment related to sex and/or race from her report, not because they were not supported by evidence in the report, but because the claimant had brought a complaint of race and sex discrimination in the tribunal."

The day after Howard complained, Kelly was said to have approached her and begun "shouting at her and waving his hands", with Howard leaving in tears.

Kelly "acted in a hostile and aggressive manner" during the incident, the tribunal said. The judgment was also critical of the way the force dealt with Howard's fairness at work (FAW) complaint.

The tribunal said Hepworth had said in evidence she "removed that conclusion because it had been suggested to her that having a reference to discrimination would compromise the respondent's [the Met's] position at the tribunal."

A Met spokesman said: "Whilst it has never been part of the policy to delete discrimination allegations from FAW documentation, we recognise that the practice of not considering them as an integral part of the process has caused concern and this will form a key part of the policy review."

Howard's lawyers will seek compensation from the Met for injury to feelings and aggravated damages. As a serving officer, she cannot speak to the press without Met permission.

Daurka said the Met's comments after the judgment showed "they don't seem to think they've done anything wrong, they don't seem to take racism seriously", and said the officer "deserved" an apology from the force.

"This judgment is a damning indictment on the Met. The conduct of the Metropolitan police and some of its senior officers towards Carol Howard was deplorable over the last two years," she said. "My client was subjected to discriminatory treatment because she is black and because she is a woman."

"Fifteen years after the Met was branded 'institutionally racist' they have failed in addressing discrimination which pervades the system. This case shows that there needs to be a complete rewrite of the Metropolitan police's equality procedures and an independent investigation into existing measures purporting to deal with discrimination complaints. That's the only way to protect officers facing similar discrimination in the future."

Howard was supported in her case by the Metropolitan Police Federation, a staff association. Its chairman John Tully said: "It is of concern that such issues are still prevalent in the Metropolitan police service, despite the many measures introduced to address the problem."

The Met said Kelly, now serving as a sergeant, had received "management action" over his supervision.

The Met also said: "Through the legal process of disclosure, the MPS provided the earlier drafts of the fairness at work documentation to the tribunal.

"Quality assurance is conducted at various stages within the FAW process to ensure that any findings and conclusions reached are based upon evidence."