The first openly gay former NBA player says prejudice against homosexuals is rife in British sport, especially soccer.

Retired British player John Amaechi on Wednesday described anti-gay sentiment in sporting bodies and on the field as a "massive problem" that was often ignored or "relegated".

The former player for the Cleveland Cavaliers, Orlando Magic and Utah Jazz says "in sport there are institutions that haven't changed in 100 years and need to." Singling out soccer, Amaechi says "if you compare their emphasis on racism to what they've done on homophobia it's an embarrassment."

Amaechi spoke after receiving the Order of the British Empire for services to sport and the voluntary sector from the Prince Charles at Buckingham Palace.Amaechi retired from the NBA in 2004 and acknowledged in 2007 that he was gay.