Tyson Fury has withdrawn from his heavyweight bout against Alexander Ustinov after his uncle and first trainer, Hughie, was taken into hospital.
Ustinov himself was a late replacement for Fury's original opponent, Dereck Chisora, who pulled out with a fractured hand earlier this week.
Fight promoter Frank Warren said he was "very, very, disappointed for the fans.
"After Dereck Chisora pulled out because of his hand injury, we worked very hard to secure a world ranked opponent in Ustinov.
"It's sad that his uncle Hughie is in a serious condition and our thoughts are with him."
Warren said that the rest of this evening's card would go ahead, and that a rescheduled dates for the the Fury-Chisora fight would be announced next week.