Duncan Scott was in ominous form on the opening day of the British Olympic selection trials, winning gold and setting a new British record in the 200m individual medley.
The double Olympic silver medallist, who is pre-selected for the Tokyo Games, won in one minute 55.90 seconds, which took 0.74 secs off the previous GB record.
“It’s a while since we could race like this so I’m really grateful and delighted with a big personal best,” said the Scot, 23.
Second-placed Joe Litchfield’s time of 1:57.74 should see him join Scott in Tokyo.
Adam Peaty also impressed, winning the 100m breaststroke in 57.39 secs.
The Olympic champion has now recorded the 20 quickest times in the history of the event.
“I’ve had a lot going on with a kid and moving house so I’ll take a lot of confidence from that going into the summer and the Olympics,” he said.
World silver medallist James Wilby, who like Scott, Peaty and Luke Greenbank has been pre-selected for the Olympics, was again the runner-up in a strong 58.76 secs.
Kieran Bird produced the shock of the day to win the 400m freestyle final in three minutes 46 seconds, inside the Olympic consideration time.
The 20-year-old beat rising star and favourite Tom Dean into second, with 1500m Commonwealth silver medallist Daniel Jervis third.
Welsh swimmer Harriet West was another to deliver a breakthrough performance, achieving the Olympic consideration time with 57.79 secs in the 100m butterfly final.
English Commonwealth champion Aimee Willmott, who considered retiring after Rio 2016, looks set for her third Games after also achieving the qualifying standard in the 400m individual medley.
Double European short-course champion Freya Anderson effectively sealed her maiden Olympic place with victory in the 200m freestyle final in 1:56.80.
Although the Olympic selection trials are the main opportunity for swimmers to gain places at the Tokyo Games, they will have further opportunities to qualify via the European Championships in May and the Mare Nostrum series in early June.