According to this passage, how is the word center spelled in British English?

Today I am going to talk about the differences between British English and American English. To begin with, some of the spelling of the British English are really different. Words like theater and center end in "re" in England instead of in "er" the way the we Americans spell them. And color is another more example. In fact, many words, which end in "or" in American English, are spelled "our" in British English. However, if someone comes here from England, we can all understand what he is saying. So spelling doesn’t really matter that much. Besides, there are some differences in pronunciation and meaning too. I remember seeing an English movie where the actors kept calling their apartment a flat. Half of the movie was over before I realized what they were talking about. And pronunciation is different. In a word, British English and American English are different, but not so different that prevents us from understanding each other.