Why British culture and literature? Why not Australian, Canadian, American, that of New Zealand or any other English speaking country? Very few students of English throughout the world are learning so that they can engage in British culture or literature, those that are are probably looking at entry to a British university. English is an international language spoken by eg: Chinese people doing business with German people - British culture doesn't come into this. On the other hand culture as a topic is important - the German people I mention above are going to need to know something about bowing and the exchange of business cards and the Chinese will need to know about taboos and customs in Germany if they travel there. The issue therefore is world culture in terms of social norms and taboos, turn taking, proxemics, and customs such as shaking hands, bowing and sniffing the tops of children's heads in Mongolia. Double decker red buses and Charlotte Bronte are nothing to do with International English language learning. I am from London by the way.

I am also of the opinion (as rhunt) that what learners are taught / introduced to must be related to their goals. For example, in a business setting, some information about the cultural/business norms of a country and/or intercultural communication will probably be helpful. If they are planning to study then they'll need EAP and some knowledge of hoe the education system works in the country they're heading for. The level of detail will also be directed by what students want to do with the language. Knowing that London has red buses, for example, is probably  not going to help them. But knowing how to ask about when buses go / which bus they need is important, as well as perhaps knowing that you (usually!) have to get on a bus at the front in Britain and pay a fare according to where you're travelling too. If they're going to London particularly, then knowing how the Oyster card system works will also be advantageous, for example. So I would suggest that you analyse why your students are learning English and then include some information on that aspect of life in the country they're likely to be using the language in.

Literature is a bit different. I think that in can (as Sureshr points out), give us a lot of information about culture, traditions, etc, but the question is whether students could access this information more effectively from another source. Of course it depends on the "literature" you choose! There are some great short stories that explore specific topics, and also some that lead to great classroom discussions about aspects of life/culture in a particular country. I don't think it's necessary, however, for learners of general English to read 'great works of classical literature', as they're probably not going to learn too much that's relevant to their aims and that they couldn't find anywhere else. Reading, though, is an important skill and using some short stories / short novels in class can promote this very well, as students will have to have read the text to be able to complete and participate in classroom activities.However, if you're restricted to using the Berlitz method, this could prove difficult to integrate...! ( I know, I worked at Inlingua!)

In summary, I would say it depends entirely on what the students are going to need to do with the language they're learning - why not ask them what they'd like to cover?

Best
CMF