BUDAPEST - Britain's Adam Peaty broke the men's 50m breaststroke world record for the second time in just a few hours on Tuesday by clocking 25.95 seconds in the semi-finals. The 22-year-old had broken his own record, set at the 2015 world championships in Kazan, when he swam 26.10secs in the morning's heats, with the final to come on Wednesday.

"This morning prepared me to do a world record again, it was just me easing through the stroke, touching the wall, progressing to the semi-final," said Peaty. "It was the same tonight, I was on such a massive high from this morning. I've learned from the experience that I've had the last two years. I came in tonight, I actually thought I'd go slower as I was a little less energetic, but tomorrow's the day to do it."

Having won the 100m breaststroke gold on Monday, Peaty showed his blistering form over the shorter distance by breaking the 26-second barrier. The scorching time left his rivals in his wake as Brazil's Felipe Lima was 0.73secs back, while South Africa's Cameron van der Burgh was third fastest into the final at 0.79. "It's impressive eh, he's the first one in history (to go under 26 seconds)," said Van der Burgh. "He's a legend, it's a privilege to watch such amazing swimming in my lifetime." However, Lima insisted Peaty will not have everything his own way on Wednesday. "It's insane, but the final will be another race," said the Brazilian.

Katie Ledecky of the United States made history on Tuesday by becoming the first woman to win 12 world swimming championship gold medals with victory in the 1500m freestyle. Ledecky clocked 15 minutes, 31.82 seconds with Spain's Mireia Belmonte taking silver at a huge 19.07secs back, while Italy's Simona Quadarella earned bronze at 22.04.

The 20-year-old is now the most decorated woman in world swimming championships history as she passed compatriot Missy Franklin, who has 11 world titles. But despite her achievement, Ledecky said winning is not as easy as she makes it look. "It's hard the other 364 days of the year, it's about putting the work in during practice, so that then I can step up," she said. "I then know that I have the work in the bank and can post those good times."

This was Ledecky's third gold of these championships -- from a possible six she could finish with -- and she led from the start. "I was a good position, holding a good pace and held steady there, I probably could have raced a bit harder in the last 50 metres, but I'm still happy with the swim and the time," she said.

King breaks women's 100m breaststroke record: Lilly King of the United States broke the world record for the women's 100m breaststroke on Tuesday in winning the gold at the world aquatics championships. King clocked one minute 04.13 seconds in the final, beating Ruta Meilutyte's 2013 record, with compatriot Katie Meili taking silver, 0.90sec back, and Russia's Yuliya Efimova earning bronze at 0.92.

China's Xu wins men's 100m backstroke world title: China's Xu Jiayu won men's 100m backstroke gold at the world aquatics championships on Tuesday. The 21-year-old Olympic silver medallist clocked 52.44 seconds with American duo Matt Grevers earning silver, at 0.04sec back, and Olympic champion Ryan Murphy taking bronze at 0.15.

"My main aim is to break the world record," admitted Xu, who fell short of Murphy's record of 51.85secs set at the Rio de Janeiro Olympics last year. "In the semi-final, I was more relaxed and thinking clearly, but I was a bit nervous in the final. I'm a little disappointed not to break it, but of course I'm happy with the win."