Nigeria has warned its citizens to be wary of fraudsters when they travel to the United Kingdom.
Nigerian scams often involve an up-front payment for a promised share in millions of dollars
The information ministry said there had been an increase in robberies and other crimes suffered by Nigerians in the UK.
The ministry said thieves used tricks like "pouring tomato juice... upon their victim's dress, and then offer to help remove it", before robbing them.
Nigeria is known for its "419 scams" in which gullible businessmen are tricked out of large amounts of money.
Nigeria's information ministry said it was making a statement based on warnings received from Nigeria's High Commission in London.
Information Minister Frank Nweke told the BBC's Network Africa programme that the government had a duty to protect Nigerians wherever they were.
"I can count off the top of my head 10 Nigerians, both highly placed and not so highly placed, who've been at the mercy of tricksters and robbers both at Heathrow Airport in London and the streets of London," he said.
"They tell you you have ketchup on your back and they're trying to help you clean it out and they clean you out as well... we think it's unacceptable."
He dismissed the suggestion that the warning was in retaliation for British government warnings to British citizens about possible armed robbery when travelling in Nigeria.
The statement said there was no evidence that Nigerians are being specifically targeted "but ostentatious dressing [and] spending... may identify a target".
"They may also feign to pick an object which had fallen under their victim's seat" in order to distract attention, it continued.
It warned that the "major flashpoints" for these crimes included airports, hotels and restaurants, high streets, shopping centres, markets, tube stations, bus stops and even inside buses.
"The occurrences have been particularly high at Heathrow Airport, Oxford Street, Piccadilly and Charing Cross," the ministry warned.
The British Tourist Authority was unable to comment.
The 419 scams, named after an article in Nigeria's penal code, usually involve e-mails making promises of a share in millions of dollars, which is to follow an up-front payment.