Isaac Chamberlain

In 2015 Chamberlain, then a 21-year-old cruiserweight from London, turned professional, outpointing the experienced Moses Matovu over four rounds on his debut, and on April 11 of that year made his second professional appearance at the First Direct Arena in Leeds.⁠[1][1]

Early in his professional career, in a fight with Wadi Camacho, he dislocated his shoulder in the third round, had it popped back in, and won on points fighting one-handed. He has said he did not have the best amateur career, turned professional at 19, and was thrown in at the deep end from the start.⁠[2][2][2]

To prepare for his “British Beef” fight with London rival and Olympian Lawrence Okolie, Chamberlain trained and sparred in Kiev from late 2017 to January 2018 alongside cruiserweights including Oleksandr Usyk and Mateusz Masternak.⁠[3][3]

On February 3, 2018, the two British cruiserweights, both previously unbeaten, met at London’s O2 Arena; Chamberlain was knocked down in the first and sixth rounds and had a point deducted for holding in the second, and Okolie won a unanimous decision by 98-89, 96-90, and 97-89.⁠[4][4][4][4]

In July 2022 Chamberlain made his first attempt at the British cruiserweight title (the Lord Lonsdale Belt), losing on points to Chris Billam-Smith in an epic fight during which he broke the orbital bone of his right eye.⁠[2]

On October 21, 2023, at York Hall in Bethnal Green, London, Chamberlain faced the previously unbeaten Mikael Lawal and won on points after 12 rounds, 119-111, 118-111, and 118-111, capturing the British and Commonwealth cruiserweight titles. After the fight he said, “Everybody fails at life, we just happen to fail in front of the whole world. You can always bounce back no matter what.”⁠[2][2][2][2]

On June 15, 2024, Chamberlain fought Jack Massey at Selhurst Park in London and lost on points, 113-115, 113-115, and 112-116, losing the Commonwealth and European Boxing Union (EBU) titles. It was the third defeat of his professional career, the previous two having come against Okolie and Billam-Smith, both later world champions.⁠[5][6][6][7]

On January 20, 2025, Chamberlain withdrew, because of a training camp injury, from a cruiserweight fight against the unbeaten prospect Viddal Riley scheduled for February 1 at Wembley in London; his professional record then stood at 16 wins and 3 losses (8 knockouts).⁠[5][7][7]

On October 13, 2025, The Venture Room released a street interview filmed on Bond Street in London, in which Chamberlain appeared as a professional boxer. In the program he said he did not come from a wealthy background and had been broke; he recalled that before his manager, Mick Hennessy, signed him, he had no fight dates and felt somewhat lost, and trained alone in Miami under the coach Jorge Rubio, sleeping in an attic and training through New Year, Christmas Day, and his birthday, and sparring with American boxers.⁠[8][8][8][8][8][8]

“No matter what happens, if you win, if you lose, people are going to live their own lives. So you’ve got to live yours and work as hard as you can.” He believes there is no need to worry about other people’s doubts, because you are the only person who spends your whole life with you (at 19:02 in the video).⁠[8][8]

“When something is inside you, it’s hard to stop.” Drawing on his experience of training alone in Miami, he explained that passion is what keeps you going (at 19:47 in the video).⁠[8][8]