George Walker: Amateur boxing champion who went into business and made millions building the Brent Cross shopping centre

In his 81 years George Walker had noteworthy careers in boxing and big business, amassing a fortune and living the high life, surviving bankruptcy and having a daughter marry into the aristocracy. His experiences in both spheres could be described as bruising. His last fight was described by a veteran boxing commentator as "unquestionably the most brutal battle I have ever seen".

In his early days he fell into criminal company, acting as bodyguard of an East End gangster associated with the notorious Kray twins and serving two years in jail for theft. Muchlater in life he was acquitted on far more serious charges involving allegations of orchestrating a multi-million pound fraud.

Throughout his life the one-time Billingsgate porter showed remarkable resilience and entrepreneurial flair. He was to sum himself up: "I suppose looking back it's been a bit of a rollercoaster of a life, far from boring, but I wouldn't change it for the world."

Born in Stepney, east London, he was one of the three sons of a drayman who had served in the RAF. Known as "the Stepney Steamroller", he had a promising early career in the ring, winning the British Amateur Boxing Championship as a light-heavyweight in the 1950s.

But one match, against Welshman Dennis Powell, turned into an epic of personal destruction, leaving Walker with broken hands, a ruptured spleen and double vision which stayed with him throughout his life. He quit the ring but became manager of his better-known brother Billy, known as "the Blonde Bomber." Although Billy was not as tough as George he was big, charming and handsome, becoming a celebrity with a large following among both men and women.

Although they would later become estranged, George used the money Billy earned to build a major business empire. It began in a small way with fast food in the form of "Billy's Baked Potatoes" restaurants. Then, following a move into the leisure business, their big break came in 1974 when George linked up with a company which owned Hendon racetrack in north London. The track was later developed as Brent Cross Shopping Centre, one of the early suburban malls, a project which produced millions in profits for the brothers. Forever restless, Walker was spurred into more and more deals.

He explained: "When I get into something new and it starts making money I look around for another place to do it. I'm like a squirrel on one of them barrels – the faster I run the faster the bloody thing goes."

Deals and acquisitions came thick and fast. Branching out into the film business he helped revive the flagging career of Joan Collins by financing her raunchy movies. He went on to buy hundreds of pubs, a chain of casinos, the Brighton Marina and the William Hill betting shops, so that by the late 1980s his deals routinely involved hundreds of millions of pounds.

The Walker family soared socially as well as financially, living variously in a particularly fine residence in Pall Mall, a gracious home in Knightsbridge and a former rectory in Essex. His children received public school educations. His daughter Sarah, described as "tall, blonde and beautiful with a cut-glass accent", married the Marquess of Milford Haven, Prince Philip's cousin. Although the marriage did not last it produced two titled grandchildren for Walker, the Earl of Medina and Lady Tatiana.

He came to commercial grief, however, when a recession arrived and the banks lost faith in his ability to cope during difficult times: at one point his company, crazily overstretched, owed 47 banks almost £1.5bn. His cause was not helped when news of his early prison sentence emerged. After bitter boardroom battles – "the banks panicked," he claimed – he was ousted as chairman of his group, Brent Walker.

Some in the city were already ill at ease with a figure who, despite his daughter's aristocratic connections, was so far outside the conventional establishment. Two other major setbacks followed when he was first declared bankrupt and then charged by the Serious Fraud Office. But the charges did not stick.

After the trial, Walker said: "I was bitter and nasty and angry – youboil with the unfairness and injustice of it all. The case ruined three years of my life but there's a lot more fight in me yet. I'm a bit knackered now but just wait."

True to his word, he launched a new phase of activity in Russia and other eastern bloc countries. "I've got myself into a different world," he enthused after gaining a foothold. "I started out with one betting shop in Moscow, now I'm in 22 countries. It's grown so big."

He acquired an impressive dacha near Moscow, complete with swimming pool and tennis court. Although his wife fondly described him as "a big softie", Walker never lost the look of a boxer, people in particular noticing his massive scarred fists.

He once explained the motivation which took him from East End gangland to the world of big business, saying: "Anyone who has been poor must have the fear of going back. It stays with you all the time – the gut fear in any man has to be a spur."

George Alfred Walker, boxer and businessman: born London 14 April 1929; married 1957 Jean Hatton (one son and two daughters); died March 2011.