Phelps breaks Olympic record
Michael Phelps became the most decorated athlete in Olympic history when his gold in the 4x200 metres freestyle relay took him to 19 medals.
Spectators at the Aquatics Centre witnessed drama and history as Phelps became the all-time most decorated Olympic athlete, Ye Shiwen defied controversy to claim a second title and Michael Jamieson became one of the quickest swimmers ever as he qualified fastest for the 100 metres breaststroke final.
Phelps moved alongside Larisa Latynina on 18 medals following the 200 metres butterfly, although any sense of achievement will have been bittersweet given he was beaten at the touch by South African Chad le Clos and had to settle for silver.
The 27-year-old then anchored the United States 4x200m freestyle relay to gold as he moved on to 19 medals, Phelps now the owner of 15 gold, two silver and two bronze medals.
The Baltimore swimmer still has three races to come and is odds-on to finish his Olympic career with 22 medals.
The Bob Bowman-trained athlete paid tribute to his three relay team-mates, and said: "I thanked those guys (in the huddle) for helping get to this moment.
"I told those guys I wanted a big lead in the last leg and they gave it to me.
"I just wanted to hold on, I just wanted to thank them for allowing me to have this moment."
Phelps had the butterfly won until the final inches but he got his finish wrong, his usual perfect spotting of the wall replaced with a glide that would have had Bowman tearing his hair out.
Phelps was disappointed but was philosophical, saying: "Obviously I would have liked to have had a better outcome in the 200m fly.
"Chad swum a great race, I have got to know him over the last year, he is a hard worker, a fast racer and a tough competitor.
"I would have liked to have won my last race, but it wasn't a terrible time. It was decent."
Le Clos was hugely emotional, crying on the podium, seemingly stunned by the magnitude of his achievement which saw the South African pip his idol by 0.05secs in one minute 52.96 seconds.
He said: "This is a dream of mine, I have always said Michael Phelps was my hero.
"I wanted to be in the final for my main event, I achieved that goal and my coach said you have done all you have to do.
"But I just remember sitting in the call room thinking that Michael Phelps has never lost this race for 10 years in international meets.
I remember turning in the last 50 and just looking at him underwater and realising this is my hero, it's crazy.
"I can't describe how I felt. In the last 25 metres, I can't explain what came over me.
"I am shocked by how many people seem to know me back home now.
"I'll have to try and defend my title in four years time, but to beat Michael Phelps is something I have wanted my whole life, it is exactly what I have been dreaming off since I was 12.
"I can't speak for Michael, but he had a great race and it was a great time too."
The British squad were sixth in the relay in seven minutes 09.33 seconds, and team member Ross Davenport said: "I managed to race Michael Phelps at the last Olympics and he won eight gold medals, the greatest Olympian ever.
"You've seen tonight even the greatest Olympians get toppled at times.
"Just being in the race with these guys is a fantastic honour.
"I'd rather be in the mix with them and standing on the podium but at the end of the day you have to hold your hands up high and say you got beaten by a better team on the day."
Meanwhile, Ye did not let the controversy surrounding her mind-boggling victory in the 400m individual medley affect her as the 16-year-old added the shorter medley title.
The Chinese swimmer had been the subject of much questioning as to how she managed to swim the final length of the longer race quicker than Ryan Lochte, winner of the men's equivalent.
Tonight she turned third after 150m before producing a blistering freestyle leg to win in a new Olympic record of 2mins 07.57secs.
Shrugging off the controversy, Ye said: "I didn't expect all the swimmers are that fast so I was really surprised and really nervous."
Britain's Hannah Miley was seventh in 2:11.29 to follow up her fifth place in the 400m race.
The 22-year-old was pleased with her performance in a race which is not her favoured event, and she also took time to give credit to Ye, saying she should be applauded for an "outstanding performance".
Jamieson proved he is a real contender in the 100m breaststroke with an astonishing time of 2:08.20 to elevate himself into the world all-time top 10.
The Glasgow-born swimmer started the day with a personal best of 2:09.84 before breaking Kris Gilchrist's British record in the heats, but his semi-final effort was truly world-class.
Only seven men have gone faster in history, with just quadruple Olympic champion Kosuke Kitajima and his Japanese countryman Ryo Tateishi quicker in textile suits.
Jamieson was fifth at last year's World Championships but a gold medal is a distinct possibility if he can recreate today's effort and manage his emotional energy.
Daniel Gyurta, the 2004 silver medallist, is second through, and not to be outdone by his Bath ITC team-mate Jamieson, Andrew Willis is third fastest in a new personal best of 2:08.47, also an English record.
Jamieson - who turns 24 the day after the swimming programme ends - said: "I knew I was going to have to improve on this morning to get into the final.
"I am swimming full of confidence and a swimmer with confidence racing in front of this crowd, it makes it a lot easier to swim fast.
"I could really hear those guys urging me home in the last 50 and I'm hoping they can make even more noise tomorrow night and myself and Andrew can shave some more time off."
Benefiting from their competitive training environment under Dave McNulty, Jamieson is not getting carried away by the prospect of gold.
"Who knows? There is a long way to go. There are some massive names in that final, guys much more accomplished than me at this level.
"But I am swimming well and full of confidence so I would just like to post another PB tomorrow and hopefully that will put me where I want."
Willis added: "I am so chuffed with that time, I knew after this morning's time that I had a PB in me.
"To come down the last length and feel that roar, it's like they are pushing you, driving you on, it gives you the sense to really go for it.
"I have a middle lane in the final, I couldn't really ask for much more.
"I hope I can sleep and I will give it a go, it's great to have my training partner in there too."
Caitlin McClatchey came seventh in the 200m freestyle in 1:57.60 in a race won by Allison Schmitt ahead of Camille Muffat, as the pair reversed their placings in the 400m freestyle.
World finalist Jemma Lowe squeaked into the final of the 200m butterfly in eighth place in 2:07.37, a relief after the shock exit of world silver medallist Ellen Gandy who was 17th in the heats.
Australian world champion James Magnussen was quickest into the 100m freestyle final.