Doncaster's Sarah Stevenson experienced a bittersweet triumph on the penultimate morning of the Games when she won bronze amid acrimonious circumstances in taekwondo's +67kg category, leaving her to consider an early retirement from the sport.

And James Degale – who trains at the English Institute of Sport in Sheffield – was crowned Britain's first Olympic boxing champion since Audley Harrison eight years ago in Sydney, opening the door on a rich future in the paid ranks.

Stevenson was forced to settle for an Olympic bronze medal after a groundbreaking ruling saw the decision of her quarter-final overturned on a day of unprecedented drama.

The 25-year-old was reinstated after officials upheld a protest against her defeat to world number one Zhong Chen.

The turbulent appeal process ultimately cost Stevenson the chance of a gold medal shot as she was pressed into semi-final action with just 10 minutes preparation.

Amid a chorus of boos from the angry partisan crowd inside Beijing's University of Science and Technology Gymnasium, Stevenson was comfortably beaten 4-1 by the more focused Mexican Maria Espinoza.

But Stevenson, who trains in Manchester, responded valiantly to seal bronze with an emphatic 5-1 victory over Egypt's Nowa Abd Rabo and claim Britain's first ever taekwondo medal.

Despite a bronze being the highlight of an Olympic career that began in Sydney as a 17-year-old and encompassed Athens four years later, the whole episode has left the Doncaster martial arts expert questioning her future.

"After today I don't know about 2012. I was on a real downer," she said. "It changed my opinion about the referees and the sport but since they changed the result I might think again."

The storm erupted in the closing seconds of her quarter-final when, trailing 1-0, she landed a sweeping kick to Chen's face which ought to have secured a match-winning two points.

Two of the four judges spotted the strike but, with a consensus of three required for the point to count, it was not recognised.

However, Stevenson and coach Gary Hall were inundated with texts and phone calls from home, detailing how clear the mistake was.

Helped by revealing television footage, a photograph and testimony from the Chinese team, the Team GB protest was upheld and Stevenson reinstated to the competition.

Team GB managed to delay the start of her semi-final by an extra 10 minutes but the lack of preparation proved costly against Espinoza.

"It did affect me in the semi-final. It was too much for me. I didn't have a lot of time," said Stevenson. "It means a lot to go through all that and actually come away with something.

"It is not a gold or silver, which I was definitely good enough to win. But after the day I had I am grateful I got the bronze."

Britain's 19th and final gold of the Beijing Games – which sealed their fourth-place finish in the medals table – was won by London boxer Degale.

The 22-year-old middleweight was one of the most unheralded of the eight Sheffield-trained boxers in Beijing when measured alongside David Price, who won a bronze, and Frankie Gavin, whose high-profile exit on the eve of the Olympics threatened to cast a shadow over the team.

However, Degale restored the smile to the face of Britain's proud amateur boxing heritage with a show of controlled and explosive boxing.

And the cocky Londoner was not afraid to let his less-fortunate team-mate know what he was missing out on.

Degale said: "I haven't heard from Frankie but I bet he's jealous. He's a silly boy because James Degale's here now.

"He could have come here and got a gold medal and been world and Olympic champion. If the Olympic Games can't motivate you to lose that last pound, you're in trouble, and Frankie knows that."

Degale followed four bouts of silky boxing with an all-out final war with Cuban Emilio Correa, whom he accused of biting in the first round of a nerve-racking bout which ended 16-14 in the Briton's favour.

And after his victory he found himself inundated with offers from promoters who will look to coax Degale out of the amateur ranks.

"I've had texts from all the top promoters already," he said. "It hasn't sunk in yet. I don't think I'll realise until I get back how life-changing it could be."