'Streets of Vice', a series that ran for a week on BBC One in late February, received a total of 58 complaints from viewers who felt that the content was unsuitable for broadcast at 9.15 in the morning.
Scenes featured in the programmes included: someone injecting drugs into their groin area; a dominatrix discussing her experiences; and a woman talking about being filmed having sex with up to 20 men.
The two programmes to receive the most complaints were one that looked at brothels and another that looked at the growth of the pornography industry. Other viewers said they were worried that because of extreme weather conditions in some areas there would be more children watching because they were not at school.
The BBC defended the series, saying that the decision to go ahead with its broadcast had been carefully considered at a senior level.
It also said that discussion of social and sexual developments was not new on daytime television, citing the example of morning talk shows that featured people talking frankly about their problems in these areas.
However, Ofcom, the media regulator, ruled that it considered the last programme unsuitable for an audience of young children.
In its ruling, the regulator acknowledged that challenging subject matter has a place in the pre-watershed schedule, but said that the programmes went beyond the normal level of discussion at that time of day.
"In this context, the scenes of drug preparation and use in the first and second programmes, and the sexual images and references in the third and fourth programmes, while far from glamorising or condoning the activities depicted and while properly acknowledging the risks posed by the lifestyles depicted, went beyond viewer expectation for BBC One at this time of day and were therefore inappropriately scheduled," Ofcom ruled.
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