MTV has been handed a £255,000 fine by media regulator Ofcom for "serious, persistent and repeated" breaches of broadcasting guidelines.
The music channel was found to have failed in its responsibility to ensure that bad language and unsuitable material were not broadcast before the 21:00 watershed.
MTV channels TMF, MTV France, MTV UK and MTV Hits were found to have repeatedly transgressed the Ofcom code in terms of protecting children from unsuitable material, observing the 21:00 watershed, justifying potentially offensive material in context and ensuring that foul language was not broadcast before the watershed.
The Ofcom report said it had received a number of complaints and cited music videos such as Aphex Twin's Windowlicker and reality shows such as Totally Scott-Lee and Totally Jodie Marsh.
The Ofcom report said the material in question was "not justified by the context of broadcasts that were likely to appeal to children".
It added that the "likely audience would have expected to have been protected from the most offensive language and material in such programming".
In response, an MTV spokesman said: "MTV Networks Europe takes this sanction and fine very seriously and has taken a series of steps to minimise as much as possible any breaches in the future.
"These include strengthening procedures regarding programmes for pre-watershed broadcast, reviewing MTV's archive programming, increasing the number of staff involved in compliance and investing in a new channel management system."