The Duke of Cambridge has promised his support to England's players if they suffer any racist abuse at the World Cup in Russia.
The Russian Football Union were fined £22,000 by FIFA for racist chanting in a March friendly against France in St Petersburg, one of several incidents prompting concerns ahead of the tournament which kicks off this month.
Protocols are in place if anything flares up during matches, England manager Gareth Southgate has said, while defender Danny Rose has told his family not to travel to Russia to cheer him on.
In conversation with the England players, William said: "Hopefully there is no racist stuff. Hopefully we won't see any of it."
William, who will not attend the World Cup, then added: "I will come down on it like a tonne of bricks."
The Duke met Southgate and captain Harry Kane before speaking to the England players at West Riding County Football Association in Leeds ahead of their friendly against Costa Rica.
He asked Kane if the rivalry between players from different clubs was put aside when they gathered together on England duty.
"There's been talk recently about a divide but here everyone just cracks on," Kane said. "We all get on so well, everyone mixes and the lads are just playing (video game) Fortnite."
Speaking to Southgate, William acknowledged the pressure and expectation which always accompanies England teams in international competition, but added: "I hope because there are so many young players everyone has realistic expectations.
"I will be watching on TV and shouting at my TV if someone does a bad tackle. It's good because I am the president of the FA I have to behave myself."
William also presented Liverpool defender Trent Alexander-Arnold with the shirt he will wear when making his senior England debut against Costa Rica.