Jamie Cooke has set a world record for the modern pentathlon 200m freestyle for the second time this month.
The 20-year-old set the long-course record at the Olympics test event on 9 July, where he finished ninth overall.
And he took more than two seconds off his own short-course record with a time of one minute 50.05 seconds in the European Championships semi-finals.
He won the swim in his semi by over eight seconds and said: "I felt really good so I just went for it."
Fellow Britons Sam Weale, Nick Woodbridge and Rob Flack are also competing for a place in Saturday's final.
The top-eight finishers will achieve the London 2012 Olympic Games qualifying standard.