The entire ai'm of the film is to make fun of the way Hollywood treats wars; ie, no matter what war it is, one American saves the world. See picture
In the film, Winston Churchill is an American GI who single handedly defeats the Nazis, and is played by Christian Slater. There's a lot of 'Oh, I wish I was American!' and 'God Bless America' from everyone, and at the end, it turns out that Shakespeare, Darwin and other great Britons are also American
I found it funny because it uses all the stereotypes Hollywood uses for English people but ironically; so all the lower class people are 'cockney irish', and everyone else has really posh accents. It is totally hilarious, and has some smexi British comedians in it, like Jon Culshaw, Harry Enfield, Vic and Bob and Rik Mayall <-- my all ti'me god
So all go and rent it Good kiddies