The logo for the 2012 Olympics was launched in June
The BBC has been criticised for showing a 2012 Olympics video logo linked with triggering epileptic seizures.
TV watchdog Ofcom received eight complaints after the London logo was shown on three news bulletins in June.
Ofcom ruled the BBC had breached its code which says broadcasters must minimise the risk to viewers with photosensitive epilepsy (PSE).
The BBC accepted there may have been a risk but that there was no indication in advance there might be problems.
The images were broadcast in reports on 4 and 6 June on the launch of the logo for the 2012 Games.
Those who complained, including the British Epilepsy Association, were all concerned that broadcasting the animated logo could cause seizures among people with epilepsy.
The watchdog said the BBC had been asked to comment on the transmission on 4 June of a sequence containing rapid flashing images.
The BBC did not broadcast what appeared to be the more problematic of the images on 6 June, Ofcom added.
The corporation said it expected that the organisers of such a major event would already have taken steps to ensure there were no problems.
It added it was alerted to the problem only when it received calls, texts and e-mails from viewers.
Ofcom concluded that a brief, two-second sequence contained an excessive number of flashes.
The watchdog went on to say that it is the responsibility of broadcasters to ensure material complies with the code.
The animated part of the logo was removed from the 2012 Olympics website after the fears over epilepsy were raised.