A Channel 4 poster campaigning promoting 'Big Fat Gypsy Wedding' will be probed by the advertising watchdog despite a previous ruling not to.
The promotion campaign caused controversy with its 'Bigger. Fatter. Gypsier' slogan, prompted 372 complaints that it was offensive and racist.
Watchdog the Advertising Standards Authority (ASA) first decided not to investigate the ads, but u-turned on Tuesday after saying their original decision was "flawed."
A spokesperson for the watchdog said: "The ASA Council carefully and thoroughly assessed complaints about Channel Four’s ads for the TV programme 'Big Fat Gypsy Wedding'.
"It will give equally careful consideration to the points that the Independent Reviewer of ASA Adjudications, Sir Hayden Phillips, brings to its attention."
David Enright, a partner with Howe & Co solicitors, who have been representing the ITMB and a number of individual travellers and gypsies who complained about the campaign, said: "This is a great day for travellers and gypsies, who were outraged by Channel 4's advertising campaign which they felt racially demeaned them and their community and exposed their children to bullying and abuse.
"We were shocked when the ASA initially decided not to investigate the hundreds of complaints it had received about this advertising campaign.
"However, the ASA has clearly been forced to look at this matter again and realised how serious it is. We hope that their investigation will now result in new guidance on adverts about travellers and gypsies."
Yvonne MacNamara, director of the Irish Traveller Movement in Britain, said it was a victory for "travellers and gypsies.": "It may prove a turning point as to how travellers and gypsies are portrayed in the media.
"Channel 4 has made a fortune out of their documentaries, which many travellers and gypsies believe have invaded and misrepresented their lives. We hope this decision may herald an end to the negative caricaturing of travellers and gypsies in the wider media."
Channel 4 and Honda each said: "We will await the outcome of the investigation."