Stand aside Michael Phelps, the teenagers have made the biggest splash at London 2012

US swimmer Katie Ledecky (left) reacts after she won gold next to third-placed Britain's Rebecca Adlington after they competed in the women's 800m freestyle final (GETTY IMAGES)

They came, they saw, they conquered and now they go back to school. While Michael Phelps will return to Baltimore having cemented his place in history with another barrow load of Olympic gold, even he has been upstaged in the Olympic pool by a quartet of teenagers.

The story of the week in the London Aquatics Centre was a fairytale written around two schoolgirls from the US and one from Lithuania via Plymouth. The fourth is more complicated. The fear is it might prove to be taken from a Brothers Grimm tale.

Ye Shiwen was the first teenager to propel herself into the limelight on opening night last Saturday. The 16-year-old will return to Zhejiang province in the south-west of China with two gold medals, one world and one Olympic record. That is not all that will accompany her home. She will travel too with a cloud of suspicion that may not be dispelled for the eight years that her samples will be retained - as all now are as a matter of course - by the International Olympic Committee.

The reaction in China to the flurry of questions over Ye's achievements was to dismiss it as western bias. Ye's improvement, and do not forget she was already a world champion, was dramatic but not as startling as the times registered by Ruta Meilutyte or Kate Ledecky, both a year younger. Ledecky has knocked 20 seconds off her personal best since competing in the US national junior championships last year.

Late on Friday night, long after her stunning victory over Rebecca Adlington, Ledecky was asked a straight question. Given the doubts that surround Ye, should those not also apply to your swim as well?

"That's totally false," said Ledecky. She was unphased by the question. "I just put in a lot of hard work this year, that's all I've been doing, just progressively setting with my coach short-term goals and long-term goals, taking time off progressively. Because of that, I've been able to get down where I am here."

The bias defence deployed by the Chinese does not stand. Sun Yang, their brilliant freestyle swimmer, has shone in London, overall only the US have won more medals and accusation does not swirl around any of them.

There is one striking similarity between Ye and Ledecky. Both started swimming with intent aged six. China's intensive training programme though remains deeply controversial. "We realised long ago that our daughter doesn't belong to us completely," admitted the father of the diving gold medallist Wu Minxia earlier this week. Ye has been part of the system for a decade now and the results in the pool are plain to see.

Ledecky started swimming for her local club in Maryland at six. It was in the same year she first met Phelps. She asked him for his autograph. She saw him again on Friday night, as she waited in the call room for her final. Phelps was walking out with gold medal number 17 swinging round his neck. They high-fived. "Have some fun out there," advised Phelps.

Ledecky was now so excited that she went out too fast, only to then discover she could keep going and going. Only Adlington has ever swum the 800m quicker. Last September Ledecky and her coach had sat down and discussed their aims for the year. They decided to be bold and try and make the Olympic team. She is now a gold medallist.

"She's 15 and has got a gold medal, it's insane," said Elizabeth Beisel of her team-mate. Earlier that night Beisel, soon to turn an elderly 20, had trailed in behind Missy Franklin (taking a bronze to add to a silver for finishing in Ye's wake). It was a third gold medal for Franklin and a first world record for a 17-year-old competing in her first Games.

Franklin was no unknown when she arrived in London as she faced the busiest schedule of any woman, competing in six events. Three firsts, a third, fourth and fifth is a phenomenal achievement.

Like Ledecky, Franklin will not have much problem filling her "what I did this summer" assignment when she returns to school in Aurora, Colorado. Both go home determined to finish their schooling no matter what has happened in London. Franklin has turned down numerous commercial offers to concentrate only on her sport and her education, while Ledecky, who lives in Bethseda in Maryland, will still swim for her school team in between studies (and international duties).

What would Ledecky's classmates make of her coming home with a gold medal. "Kind of neat I guess," she said and grinned, looking every inch the teenager. In the pool she looks anything but, and neither do Meilutyte, Franklin or Ye. It is little wonder Adlington is pondering retiring at the grand old age of 23.