I think that would depend on the person. We are familiar with American terms in the UK, and it is not unusual for many Brits to say both, or to swap and change from one to the other. Often we can''t remember what is supposed to be American and what is supposed to be British. Pitch would be most commonly used for our own national games, football and rugby.

Most people would call it a field, since that is what Americans call it. However, it is a pitch for any game called football actually played with the feet. :)