It's still not clear why Liverpool fans took aim at Prince William at the FA Cup Final.

Boos rang out around Wembley Stadium as the Duke of Cambridge, who's president of the Football Association, was introduced to Chelsea and Liverpool players before kick-off.

Royal commentator Richard Fitzwilliams told Mike Hosking it's a shameful and unacceptable thing to do.

“It’s been broken bound into whether he was announced and during the national anthem and during a bit of that rather wonderful hymn Abide With Me. I mean, it’s absolutely lunacy behaviour, why indeed?”

LISTEN ABOVE