Channel 4 has responsibility to respond to "very serious viewer concerns " about accusations of racism on the Big Brother show, the broadcasting watchdog Ofcom said today.
The chief executive Ed Richards said that, in view of the 27,000 complaints made about the show, Ofcom would be taking action by writing to Channel 4 "shortly".
But he said in the meantime it was the responsibility of the channel to take any immediate action.
He added: "Clearly what is happening is very serious, any allegation of racism is very serious."
He said that Ofcom was "monitoring" the situation "very, very closely".
Mr Richards was speaking to reporters following a media conference taking place in Oxford today in which he told delegates that the watchdog would not "conduct a kangaroo court".
In response to questions from the conference floor about the deepening row surrounding the reality show, he said it was important that "due process " was used and added: "The last thing I'm going to do is sit here and give you my personal opinion."
He said: "One can think of other circumstances when people have rushed to judgment and repented at leisure."
He refused to speak about the possible sanctions that a broadcaster could face in the light of an investigation such as this, saying "we are not in that position at the moment".
He refused to answer questions from waiting reporters following his speech and instead made a short statement explaining that the situation was being "monitored".
He had earlier used his speech to urge broadcasters to embrace the coming digital age, saying: "We mustn't be scared of this. Sometimes you have to look forward and make a judgment on the way the world is going."
Russ Taylor of Ofcom Watch, a weblog set up in 2002 to comment on the watchdog's actions, said he thought it was "unlikely" that Channel 4 would be fined by Ofcom.
"They cannot treat Channel 4 any differently from other firms. I doubt they will be fined. Channel 4 is Government-owned and often held up as an example of good broadcasting, it would be an unusual step, so to allow one episode to jeopardise that would be a shame."
"If any damage has been done in that house, and I think it has, then it has already happened. It is not Ofcom's role to be part of the scrum. They must stand back from it.
His business partner, Luke Gibbs, said that the watchdog's role was "to provide balance".
He said: "It will interesting to see how they respond to the political pressure. They don't operate in a vacuum."