Football Association chief executive Martin Glenn has told FIFA he will fight any attempt to fine England for wearing poppies in Friday's World Cup qualifier against Scotland at Wembley.
Both teams are set to defy FIFA's ban on messages it considers to be commercial, personal, political or religious by wearing black armbands with embroidered poppies to mark Armistice Day.
The FA and the Scottish FA had hoped to do this without punishment -- as they and the Football Association of Wales had done in three November friendlies in 2011 -- but the new regime at world football's governing body has refused to sanction an exception to the game's laws.
FIFA general secretary Fatma Samoura reiterated law four, paragraph four, which states that players' equipment must be free from such messages.
Samoura pointed out that the law was brought in by the International Football Association Board, comprised of the four British home nations and FIFA, and said it must be "applied uniformly" for it to have authority.
But speaking to journalists at a Sport Industry Breakfast Club event in London, Glenn said: "If they [FIFA] fine us, we'll contest it. They have much bigger problems they should be concentrating on. "I'm confident our legal position is right and our moral position is right. Our case is absolutely rock solid."
Glenn, FA chairman Greg Clarke and their counterparts at the SFA have previously said they do not think wearing a poppy to commemorate those who have died in armed conflicts is a political message.
They said the 2011 compromise agreed with the previous leadership at FIFA should apply.
England midfielder Jordan Henderson told a news conference he believed it was "very important for the country, for the players, to remember what those people have done for this country."
The Football Association of Wales has conceded defeat in its bid to wear a poppy against Serbia, saying players will don black armbands instead as the organisation cannot "take the risk" of a FIFA fine or point deduction.
Northern Ireland's players will do the same in their clash with Azerbaijan, but there will still be a minute's silence at Windsor Park on Friday night, while a card motif featuring a poppy will also be displayed in the West Stand along with other Armistice Day tributes.
"FIFA has turned down a request made by the FAW for the Wales national team to wear poppies on their shirts or armbands," said an FAW statement.
FAW chief executive Jonathan Ford said: "The FAW naturally wishes to respect and honour those who fought and lost their lives fighting for their country. As an Association we have to respect the rules of FIFA and following long discussions with members of the FAW Council, staff, management and players, a decision has been made not wear the poppy against Serbia.
"We felt unable to take the risk of a financial penalty or point deduction, however as we always have done at this time of year, we will be paying our respects in other ways."
Asked about the IFA's decision not to follow the FA and SFA's lead on poppies, Northern Ireland manager Michael O'Neill said: "I have a lot of influence, none of it exists at FIFA.
"This is a decision that is made by FIFA, I think the association have done everything in their power to mark the occasion with the utmost respect, we will do that as a group as well.
"We didn't feel it was the right thing as an association to violate the regulation. As a group of players and as a management team we're happy that the decision's been made and we can focus on the football now."