A Met officer faces the sack for gross misconduct after he was convicted of launching a foul-mouthed tirade at an Asian takeaway manager.
Pc Philip Juhasz, 31, hurled abuse at Pakistani Umer Nazir, 23, at the Delice de France snack kiosk at King's Cross railway station last September.
The shop manager said the off-duty officer had demanded to be sold food that was about to be thrown away for half price.
Juhasz was convicted of a racially aggravated public order offence at Westminster Magistrates' Court on March 23, police said.
It comes after a former member of the Stephen Lawrence inquiry panel said blame for routine racism within the Met rested with senior officers and is more endemic than Britain's biggest force is willing to admit.
Dr Richard Stone's reported condemnation came after Superintendent Leroy Logan, of the Black Police Association, said warnings of racism at Scotland Yard have fallen on "deaf ears" for more than a decade.
They spoke after 10 complaints of alleged racism - relating to 18 officers and one member of police staff - were referred to the police watchdog.
The referrals came just days after Scotland Yard vowed to get to the bottom of "very damaging" footage of one officer apparently racially abusing a man and another allegedly assaulting a teenage boy last summer.
Referring to the murder of Mr Lawrence in an open letter to Commissioner Bernard Hogan-Howe seen by the Independent, Dr Stone said: "Here we are 14 years later with the worst kind of blatant and violent racism by police. Even worse is that the officers appear to be doing it openly in front of colleagues from whom they have no fear of being reported."
He added: "Such a group of constables could not be routinely racist like this without their seniors being aware, and telling them to stop. I fear this may alas be more than 'just a few bad apples'."
CORRECTION: An earlier version of this story stated the officer was from the British Transport Police. This has been amended.