1970s
In 1970 Bugner emerged internationally as an outstanding young prospect and was world-rated by the end of the year. He won nine consecutive bouts that year, including victories over well-known boxers such as Chuck Wepner, Manuel Ramos, Johnny Prescott, Brian London, Eduardo Corletti, Charley Polite and George Johnson.
Bugner was now positioned to challenge world-rated Englishman Henry Cooper, who had nearly knocked out Muhammad Ali a few years previously, for Cooper's British, British Commonwealth and European titles. However, because Bugner was still too young to fight for the British Commonwealth title (the minimum age was twenty-one years old at the time), this much-anticipated bout had to be postponed until the following year. While waiting to come of age, in 1971, he defeated Carl Gizzi and drew with Bill Drover just weeks later and weeks before facing Cooper.
In March 1971, Bugner met veteran Cooper and won a fifteen-round decision. Bugner won the bout by the slimmest of margins, 1/4 point, on the card of the lone official, Harry Gibbs. The British sporting public and press were deeply divided about the verdict. Many felt that Cooper deserved the decision due to his steady aggression. But Bugner fought effectively on the defence and often scored with his left jab. The Times, among others, scored the fight in favour of Bugner. The outcome of the bout was regarded as controversial for many years.
Nonetheless, Bugner was now the British, British Commonwealth and European champion, and for the first time, he was ranked among the world's top ten heavyweights. Bugner would remain in the world ratings for most of the 1970s.
Bugner retained his European title with a decision over tough German heavyweight Jürgen Blin. However, later in 1971, Bugner surprisingly lost decisions to underdogs Jack Bodell and Larry Middleton; sandwiched between these losses was a victory over Mike Boswell. The Bodell fight was particularly costly, depriving Bugner of his British, British Commonwealth and European championships. Bugner's relative inexperience, his youth and lack of an extensive amateur background were the chief causes of these defeats.
In 1972 Bugner won eight consecutive fights, including a knockout over Jürgen Blin for the European championship. By the end of this, Bugner demonstrated much-improved ring ability and acquired enough experience that his manager began seeking matches against the world's best heavyweights.
Bugner began 1973 by retaining his European belt with a victory over the capable Dutchman Rudie Lubbers. The 23-year-old Bugner then lost twelve-round decisions to Muhammad Ali and Joe Frazier. Despite being clearly defeated, Bugner fought well and won the respect of the boxing media and the public alike. After their bout, Ali declared that Bugner was capable of being world champion. Ali's trainer Angelo Dundee later echoed that sentiment. The fight with Frazier in July 1973 at Earls Court in London was deemed a classic. After being knocked down by a tremendous left hook in the tenth round, Bugner arose and staggered Frazier to close the round. Frazier took the decision, but only narrowly, and arguably only George Foreman and Muhammad Ali ever gave Frazier a harder fight. Many regard the Frazier bout as being Bugner's best career performance.
After the Ali and Frazier fights, Bugner won eight bouts in a row, his most notable victories being over ex-WBA world heavyweight champion Jimmy Ellis, and Mac Foster. By the end of 1974, Bugner was rated among the top five heavyweight contenders in the world.
Bugner challenged Muhammad Ali for the world championship in June 1975, the bout being held in Kuala Lumpur, with Ali winning a relatively one-sided fifteen-round decision. Bugner performed fairly well but maintained a strictly defensive posture throughout most of the fight, perhaps due to the blistering tropical heat, and as a result, he was widely scorned by the media and public. In an interview during an April 2008 reunion with Henry Cooper, Bugner defended his tactics in the Ali fight as having been necessary due to the extreme temperature and humidity of the outside venue.
Early in 1976, Bugner announced his retirement from boxing, stating that he no longer felt motivated to fight professionally. Within months however he returned to the ring, expressing disgust at Richard Dunn's performance against Ali and in October, he defeated Richard Dunn with a first-round knockout to reclaim the British, British Commonwealth and European championships.
In 1977, Bugner lost a close twelve-round decision away from home to top contender Ron Lyle. The scores were 57–53 and 56–54 for Lyle against 55–54 for Bugner. After this bout, Bugner again retired, making only sporadic comebacks to the ring over the next decades.
