Adam Peaty will miss the mixed 4×100 metres medley relay final after returning to the pool on Saturday morning and describing how he has had the “worst week” physically.

Peaty helped Team GB win the inaugural event at Tokyo 2020 but he missed Friday’s heats following a positive Covid test, hours after claiming silver in the men’s 100m breaststroke on Sunday night.

While Peaty featured in the men’s 4x100m medley relay preliminaries, Team GB named Kathleen Dawson, James Wilby, Duncan Scott and Anna Hopkin as the line-up for the mixed showpiece on Saturday evening.

Peaty revealed after helping Team GB qualify for Sunday’s men’s final that he has had a turbulent past few days and has also picked up other ailments including an ear infection – although it is unclear whether this is connected to him having had coronavirus.

“It’s been a rough, rough week but hopefully we’ll find our way through the next 36 hours,” said Peaty.

“(It’s) probably (been) the worst week of my life in terms of how my body is – and that is no exaggeration.

“Everything’s come at once and since Covid, I’ve been waking up every day with a different thing.

“The medical team has been brilliant and it’s just a victory getting on that starting block. Now hopefully, that will give my body a nice, little push for tomorrow.”

Peaty, alongside Oliver Morgan, Joe Litchfield and Matt Richards, finished second in their heat and qualified fifth fastest overall, with France – led by Leon Marchand – topping the time sheet.

Marchand, who collected his fourth individual gold medal on Friday night, swam the breaststroke leg in a separate heat and is now set for an eye-catching showdown against Peaty on Sunday.

But Peaty, whose leg of 59.16 seconds was just 0.11 secs slower than his time in last week’s men’s 100m breaststroke final, admitted he will not be firing on all cylinders this weekend.

“I’m glad I’ve got a heat swim,” added Peaty. “It’s my first hard stuff since the final on Sunday last week.

“If I’m not well, I’m not well. I’ve been brought up in the system by (coach) Mel (Marshall) that if you’re not well, you still go.

“I’ve only got two days left. I’m not going to be 100 per cent, I know that, but I’ll give my best effort and that will hopefully give me a nice time.”

For the mixed event, Dawson will be on backstroke duties, Wilby is in for Peaty for the breaststroke, Scott will take the butterfly leg while Hopkin will finish off on freestyle.

Scott, who replaces Joe Litchfield in the only change from Friday’s heats, has the opportunity to win his ninth Olympic medal, which would draw him level with the Team GB record of nine, currently held by cyclist Sir Jason Kenny.