Adam Peaty starts his quest to become the first British swimmer to retain an Olympic title this weekend but attention will centre on whether another world record in the 100 metres breaststroke will fall at his feet.

The 26-year-old is redefining what appears possible in his event, where he is undefeated in major competitions in seven years and his current best time of 56.88 seconds is more than a second quicker than anyone else in history.

Much of the focus will be on whether he can lower that benchmark even further in Saturday's heats, Sunday's semi-final or Monday's final, rather than if he can successfully defend the gold medal he won five years ago.

His time of 57.13secs in the Rio 2016 final set a new standard, after which Project 56 was born and then conquered at the World Championship two years ago. Peaty estimates he can go as low as 56.2s or 56.3s at his absolute best.

There are many medal hopefuls in Tokyo over the next week or so – including Molly Renshaw in the 200m breaststroke, Duncan Scott in the 200m freestyle and James Wilby, even if he seems to be a distant threat to Peaty's supremacy.

But many eyes will be drawn to Peaty, who welcomes the attention and all the attendant burden that can bring.

"Down that last 50 metres at the Olympic Games I know I've got the whole country on my back and behind me," Peaty added.

"People would think 'I don't want that pressure' but if you want to be the best in the world, you've got to take that and welcome it and find a way to perform under that.

"You get it a lot in pretty much every interview about dealing with the pressure going in, nobody's ever defended an Olympic title but I'm one of the most chilled out people to possibly do it.

"That's just me, I'm very chilled and I know exactly what process I've got. But it's an Olympic Games, it's fun. Win or lose, nothing really changes in a sense, I'm just completely free."

While Arno Kamminga became the second person to breach the 58-second barrier at the Dutch trials earlier this year, Peaty is understandably bullish that if he is at his peak then he is close to untouchable.

"It's not an arrogant thing, it's just a mindset we've built up where there's a certain difference between going out there to get gold by 0.04 seconds from the next guy and going out there to dominate," Peaty added.

"I train like I'm in second but I perform like I'm in first. I want to go out there and do what I do, and if I do perform then I don't think many people would get close."

Max Litchfield, Brodie Williams, Aimee Willmott, Harriet Jones and Kieran Bird are among the other Britons taking to the pool in their various disciplines the day after the opening ceremony.