British runner Josh Kerr broke the world record for mile time on Saturday in London, at 3 minutes and 42.66 seconds. Kerr beat the record last set by Moroccan runner Hicham El Guerrouj in Rome in 1999, at 3 minutes and 43.13 seconds, by nearly half a second.

Kerr publicly announced his bid to break the mile world record in late March, in a track season without either Olympic games or world championships.

“It’s very overwhelming with the amount of hype,” he told BBC Sport after breaking the record. “It’s silly to call your shot that early, obviously a lot of things can go wrong. But I’m surrounded by amazing people, and I was able to just stay consistent, put the work in.”

The 28-year-old from Edinburgh holds an Olympic silver medal in the men’s 1500m from the 2024 Paris Games, and is the 2023 world champion in the same distance.

Kerr and his sponsor Brooks Running called the mile world record attempt “Project 222,” referring to the number of seconds he needed to be at or under to break the world record.

Unlike Kerr’s other races, Project 222 was laser-focused on the time goal.,said Kerr’s coach Danny Mackey, in an Instagram video before the race. The team watched out for whether anyone else had broken the world record before the July meet. “That can change the math a little bit — but we generally know what he needs to run on July 18th,” Mackey said.

Kerr trained in the high altitude of Albuquerque, N.M., and documented his training in a series of YouTube videos. Brooks Running made him custom spikes and a speed suit. Their plans seem to have pulled off smoothly on Saturday. Two training partners kept him on pace to beat the record, and Kerr also beat the second-place finisher, American runner Yared Nuguse, by about 3 seconds. The UK’s Jake Heyward finished third.

He’s now part of a rich lineage of British runners to break the mile world record, and the fact that he was able to smash the record time in the UK, at the Wanda Diamond League meet, carried special significance for Kerr. “We dug into the history of [the mile] with six previous British holders of [the record] … I would be the seventh, and to do it on British soil,” he said in an interview with FloTrack when he announced the bid.

One of the British record holders, Roger Bannister, was the first athlete to run the mile in under four minutes, in 1954. Two other British record holders, Sebastian Coe and Steve Ovett, traded the record three times over the course of 10 days in 1981.

Kerr is an alumnus of the University of New Mexico, where he competed in the NCAA. He held the collegiate record in the men’s 1500m from 2018 until 2021, when it was broken by Nuguse, Saturday’s second-place finisher.