Image caption The scene was broadcast shortly before 10:00pm

The BBC has responded to hundreds of viewers who complained about violent scenes in BBC One's Silent Witness.

Sunday's episode culminated in a scene in which a prison officer, played by Leo Gregory, beat and kicked an inmate on the floor of a toilet cubicle.

The BBC said 483 people had complained the story was "too violent".

A statement said it had been felt the scenes would not go beyond viewers' expectations, but "we're sorry if you felt we got it wrong on this occasion".

Sunday's episode of the crime thriller was watched by 6.1 million people. The second part, broadcast on Monday, saw that figure drop to 4.7 million.

Both episodes were shown after the watershed, and carried a pre-programme announcement, warning viewers of violent and upsetting scenes.

While the climactic scene hid much of the violence behind a closed door, viewers could hear the screams of the victim, and saw blood leaking out onto the floor.

Some people voiced their complaints online. "For the first time ever a programme made me feel physically sick," wrote one contributor on the Digital Spy message boards .

Image caption The episode starred Emilia Fox and Tom Ward (left) with Leo Gregory playing prison guard Daniel Kessler

"The cubicle scene went too far," wrote another.

"I don't want this series to turn into one of those dreadful torture porn dramas we see elsewhere on television."

In its statement, the BBC said: "We acknowledge that certain scenes may have been challenging but we filmed and presented them in such a way as to make sure that, although as a viewer the implication was there, it was never actually shown."

"As programme makers we take our responsibility to the audience extremely seriously and try to make sure we strike the right balance between compelling drama without being unnecessarily graphic."

Broadcasting watchdog Ofcom said it had received 35 complaints about the show.

It is currently assessing these and no decision has been made on whether to launch a formal investigation.