How is American NFL football received in England? It's hard to tell from TV. The stadium looks pretty full. But, it doesn't give much of a sense of how much the average Brit cares. I tend to doubt if there are work place football pools and tip boards for NFL football.
I moved to England from USA in 2009 so I thought I can make a comment on this topic. Brit cares about football, but the one that's played with foot - known to American as soccer. I don't see American Football getting big in England. You have to remember one thing why American Football is so popular in America - because of its college root and high school root - which is never going to be possible in England.
Also, the weather in Britain during the winter is damp and cold. Most of the games played in London are wet and the field conditions are absolutely terrible. Players are slipping on the field and it's just an ugly game. If Britain were to introduce American football, they should start by playing in domed stadiums.
Canada is the place to expand for NFL.