By Colleen Dardagan

Low-cost airline has fallen foul of Fifa's fierce marketing laws and been forced to pull all its advertising linked to fares over the World Cup period.

The carrier has a reputation for irreverent, tongue-in-cheek marketing campaigns, but this time, according to Fifa, it has gone too far.

A multimedia marketing campaign that featured advertisements with the headline, the Unofficial National Carrier of the You-Know-What, showing stylised pictures depicting the Cape Town stadium, soccer balls, vuvuzelas and a football player has been withdrawn following a letter from Fifa threatening the airline with damages.

The campaign, which is drawing an increasing following on the Internet, also challenged other carriers to keep their fares low during the World Cup.

The airline broke the news on Twitter, saying: "Oh dear, letter from Fifa's lawyers says we broke their trademark of the use of 'South Africa'. commented that "even the use of our national flag was an issue. It is absolutely outrageous. We have signed over our country, its symbols and our economy to one Sepp Blatter. Nasty". marketing manager Nadine Damen said the airline had been surprised to receive the letter because the ad was true to the brand, which was quirky and fun.

"Fifa is complaining. They said we cannot depict the Cape Town stadium . soccer balls ... the word South Africa, the national flag, can't make any reference to the World Cup and cannot use the vuvuzela.

"We chose the images and words carefully so as to acknowledge the World Cup period, but not infringe on their trademarks, but it seems we have crossed their very strict line. Our fans loved the ad."

Damen said Fifa had threatened that its corporate partners could claim damages and that the campaign should be withdrawn immediately.

Fifa said its lawyers had contacted the airline to tell them that the advert breached South Africa's law against ambush marketing by seeking to gain a promotional benefit for the Kulula brand by creating an unauthorised association with the 2010 World Cup.

"Kulula's legal team confirmed their compliance with Fifa's requests," a Fifa statement said.