Channel 4 has been fined £5,000 by media watchdog Ofcom after complaints about an item on caffeine intake on Richard and Judy's TV chat show.
Richard Madeley read out the apology for Channel 4
Four viewers complained about an item that followed an apology Richard Madeley made to Red Bull over an earlier broadcast.
The viewers said that what followed the apology "seemed like an advertisement".
It is the first time Ofcom has fined one of the five main terrestrial TV channels since it was set up in 2003.
Channel 4 admitted breaching the programme code.
The broadcaster was also directed to transmit Ofcom's statement of finding.
The complaints arose from a discussion on the dangers of excessive caffeine intake on the Richard and Judy show on 18 May 2004.
During the studio discussion, four commercial examples of energy drinks - including a can of Red Bull - were displayed and experts were invited to talk about the effects of caffeine intake.
It also included the wrong information about the amount of caffeine in the energy drink Red Bull.
In the 19 July 2004 edition of the show, Channel 4 broadcast, through Madeley, an apology and correction to the previous caffeine item, stating that it had contained factual inaccuracies.
It was followed by a videotape in which the benefits of caffeine were examined, with particular emphasis on the "caffeine energy drink" Red Bull.
One viewer described it as "a sponsored advert for the coffee and Red Bull industry", while another wondered "whether the item had been produced by the makers of Red Bull and whether the broadcast was made to avoid legal action".
During an investigation, Channel 4 said objections raised by Red Bull in relation to the item broadcast in May meant there was need for a follow-up.
But Channel 4 admitted that despite its best efforts to give a balanced perspective on the issue of caffeine intake, some viewers had felt there had been a degree of external commercial influence.
Ofcom acknowledged that the July broadcast was clearly intended to make amends for the errors contained in the earlier broadcast, but was still considered to be a serious breach.
In a statement, Channel 4 said: "This item was intended to correct inaccurate information about Red Bull in an earlier Richard and Judy report, but we accept Ofcom's view that the degree of prominence given to the company was misjudged."