The corporation have issued the following statement:
We’ve received complaints from some viewers who feel it is inapproprate to show gay sex in Torchwood.
The BBC's response
We have strict Editorial Guidelines which govern the content of our programmes, and Torchwood is no exception. These clearly state:
"In all BBC output the portrayal of sex, or the exploration of sexual issues, should be editorially justified and treated with appropriate sensitivity. In post-watershed content, we must be able to justify the frank and realistic portrayal of sex and the exploration of themes and issues which some people might find offensive."
Captain Jack Harkness is an established character in the series. We felt the content was justified in terms of the context and character and would be within the expectations of regular viewers. We aim to depict relationships whether heterosexual or homosexual in an honest and realistic way. These scenes are not meant to cause offence.
(Source: BBC Complaints)