Video report by ITV News reporter Richard Pallot
Donald Trump has insisted his row with the NFL over players kneeling while the national anthem is played before games has "nothing to do with race".
A number of players have been kneeling in protest against racial injustice and police brutality in the United States.
The president called for players who take this stance to be fired, and called on fans to boycott games, sparking a row with a number of NFL officials and team bosses, as well as criticism from high profile American sports stars.
Colin Kaepernick, who remains unemployed despite leading a team to the Super Bowl at the end of the 2012 season, was the first to kneel in protest over perceived racial injustice and police brutality.
Trump has told reporters the row has "nothing to do with race", insisting it is about respect.
At an NFL game in London at Wembley on Sunday, at least seven Baltimore Ravens players and more than a dozen Jacksonville Jaguars players took a knee during the anthem while the rest of the players stood locked arm-in-arm in an apparent response to Trump's comments.
Baltimore Ravens owner Steve Bisciotti says he "100 percent" supports his players' decision to kneel, while Jaguars owner Shad Khan stood arm-in-arm with his players during the anthem.
The president has also picked a fight with NBA star Stephen Curry in recent days, after he rescinded an invite for NBA champion Stephen Curry to visit the White House after Curry said he would vote not to attend an event there.
Trump said: "Going to the White House is considered a great honor for a championship team. Stephen Curry is hesitating, therefore invitation is withdrawn!"
This drew condemnation from stars including basketball player LeBron James, who called the president a "bum".
In response to James's tweet Curry said: "That's a pretty strong statement.
"I think it's bold, it's courageous for any guy to speak up, let alone a guy that has as much to lose as LeBron does and other notable figures in the league. We all have to kind of stand as one the best we can."