I think that some of these answers are probably missing some subtleties. The first thing to realize, is that when it comes to things like this, there isn't really a single homogenous "British Culture", and attitudes to swearing will differ from local to local, between social classes, backgrounds, political groupings etc. It can be difficult for even a British person to work out the correct acceptable language is in any given situation.
The second thing is that not all swear words are equal. This is fairly obvious, but what is less obvious is that the relative offensiveness of a given word varies from country to country, and sometimes between groups within a country. So s**t is generally regarded as mild, f**k is stronger, and will shock some, but not that many, where as c**t is generally reserved for situations where offense is intended. Unless you are in Scotland, when c**t is far more acceptable.
In the UK, blasphemy is not really even regarded as swearing. Words that refer to bodily functions are somewhere in-between, and then words that refer to a persons innate characteristics are the worst. If a lecturer is using the N word, or any other racist epithet, words that refer dismissively to homosexuals, words that refer to phyiscally or mentally disabled people etc, then I probably would complain, unless they themselves possessed that characteristic (A gay person is allowed to use the term p**f, but others aren't).
All this makes for a very complex situation. Our jobs as educators is to give people the best chance of learning. Sometimes emphasis and humor can help with this, but it can just as easily impede it. So while I swear frequently in the pub, I generally avoid swearing in a lecture or other formal didactic instruction situation. However, one-on-one or in small groups where I am able to assess how people might respond, I will tailor my speech to what I think the other person believes to be appropriate.