Audley Harrison claimed his 16th straight victory since turning professional with a comprehensive points win over Julius Francis.
Harrison finally knocked down Francis in the last round
The WBF heavyweight champion, who won the belt by beating Holland's Richel Hersisia in March, struggled to overcome a stubborn opponent.
Harrison took his time to get going and relied heavily on his jab but finally started to open up in the 11th round.
The onslaught continued in the 12th and Francis hit the canvas late on.
The victory is sweet revenge for Harrison, who lost his unbeaten streak as an amateur when the pair met 11 years ago.
Francis was a late replacement for Nicolay Popov and although he was a durable opponent, he showed little ambition.
The three British judges had little doubt about who was the winner, with Larry O'Connell and Roy Francis scoring 119-109 in favour of Harrison and John Keane giving a 119-108 verdict.
"I am glad I got my first 12 rounder in the bag. Now both
myself and everybody else knows I can do that," said Harrison.
"I was trying to pace myself. I was always ahead and all in all I'm happy with that performance."
Harrison is now in talks about a possible clash with British and Commonwealth champion Matt Skelton.
"It's a question of money. We are meeting again next week to talk about that fight."