Phelps flies to 17th gold and makes a mockery of all the early doubts

Michael Phelps collected the 17th Olympic gold (Getty Images)

His work here is nearly done. Michael Phelps won his 17th gold medal, and last individual, last night with a swim that characterised every detail that has made him an Olympian like no other.

The butterfly is the event Phelps is designed for and nobody was going to stop him touching the wall first. Seventh at the turn in the 100m fly he flew through the field to roars of acclaim to win his third gold of London 2012. He is the man of the meet and how dare we ever have doubted him.

Phelps will make one final appearance tonight, swimming the fly leg of the relay medley. It is a gold medal the United States would need a catastrophic performance not to win and send Phelps back home to Baltimore to hang up 18 gold medals, two silver and two bronze next to his trunks. He has become more over-decorated than a suburban Christmas tree.

It is only the second time a title has been won by the same man as three successive Games; that feat was first recorded, of course, by Phelps as well, when he won the 200m individual medley on Thursday. This is an event in which he possesses a track record that shines even by his standards. It is nine years since he won his first world title and has defended it in 2005, 2007, 2009 and 2011, interspersed with Olympic wins in 2004 and 2008.

He has got better and better as the week has gone on and will retire on top of the world. His surge last night was inevitable, carrying him through the field, ticking them off one by one, including Chad le Clos, the 20-year-old South African Phelps has singled out as someone capable of picking up his mantle.

"I'm just happy that the last one was a win," he said. "That's all I really wanted, and this one was a bigger margin of victory than the last two combined, so we can smile and be happy. It was fun. To be able to finish that way, you can't really finish any better."

Lizzie Simmonds, sixth in Beijing four years ago, produced the swim of her life to finish fourth in the final of the 200m backstroke. The gold, and a new world record, went to Missy Franklin. That makes it three gold and one bronze for the brilliant 17-year-old, and she has another gold almost certain to follow tonight in the medley relay. Franklin finished three quarters of a second inside Kirsty Coventry's previous mark, one of those set during the height of the bodysuit era in 2009.

Britain will hope to end a disappointing week in the pool with at least one more medal. The men's medley team conjured one of the loudest roars of the week from the home crowd with a stirring swim to win their semi-final. The quartet – Liam Tancock, Craig Benson, Michael Rock, Adam Brown – began the day ranked 14th in the world and ended it as second fastest qualifiers for tonight's final.

It was an all-round performance by Britain with 18-year-old Benson the pick. The Scot – what is it about Scotland and the breaststroke? – completed his leg just 0.1sec slower than Hungary's world record holder Daniel Gyurta. It helped set Adam Brown to win the semi-final ahead of Australia. The big guns will be back for the final – including Phelps – but Britain will look to be in the mix for bronze. "That was the best experience of my life," said Benson, who will drop out of the final for compatriot Michael Jamieson, breaststroke silver medallist.

The women's medley team were sixth fastest into their final but possibly have a better chance of a medal with Fran Halsall and Ellen Gandy to come in. "The crowd is just insane," said Gemma Spofforth, who will tonight compete in her last race before retiring. "It definitely spurred me on. They just went crazy."