Mexico's ambassador in London has complained to the BBC over "offensive, xenophobic and humiliating" comments made about his country on Top Gear.
Eduardo Medina Mora has written to the BBC about "insults" made by Richard Hammond, Jeremy Clarkson and James May.
Discussing a Mexican sports car, Hammond said vehicles reflected national characteristics so "Mexican cars are just going to be lazy".
The BBC did not comment but said it would respond directly to Mr Mora.
Reviewing the Mastretta on Sunday's show, Hammond said: "Mexican cars are just going to be lazy, feckless, flatulent, overweight, leaning against a fence asleep looking at a cactus with a blanket with a hole in the middle on as a coat."
The presenters, known for their edgy jibes, then described Mexican food as "refried sick".
Clarkson said he was confident he would not receive any complaints about their comments because the Mexican ambassador would be asleep.
However, the ambassador did complain, and demanded an apology from the BBC.
"The presenters of the programme resorted to outrageous, vulgar and inexcusable insults to stir bigoted feelings against the Mexican people, their culture, as well as their official representative in the United Kingdom," he wrote.
"These offensive, xenophobic and humiliating remarks only serve to reinforce negative stereotypes and perpetuate prejudice against Mexico and its people."
It is not the first time the driving programme has caused controversy.
Hundreds of viewers complained in 2008 after Clarkson made a joke about lorry drivers murdering prostitutes.
Last week, the programme was named most popular factual show at the National TV Awards.