As per the web site, you will need to have the right to work in the EU before you join the airline, BA won't sort out work permits etc. You do not need to be an EU citizen, we have a variety of Canadians, Australians, Swiss etc. As long as you meet the criteria it makes no difference to the selection process, though with a lot of the selection process being in English it clearly helps if you have a very good grasp of it.
Good Luck!