Need to name 7 Home Grown players in your team sheet for all league games.
Home Grown means a player registered with any English or Welsh club "for a period, continuous or not of three seasons or 36 months prior to his 21 birthday (or the end of the season during which he turns 21)".
So to be picky, they don't have to be British, but yeah, basically they have to have spend 3 years in the youth system of an English or Welsh club.