Halsall (left) edged out Lowe in the final

Liverpool's Fran Halsall qualified for her third Olympic event as she edged out Stockton's Jemma Lowe to win the women's 100m butterfly in Sheffield.

Halsall and then Lowe had both lowered the British record in the heats, but Halsall claimed the national title with a personal best of 58.16 seconds.

"I swam faster than last night so I'm very happy," said Halsall, who also has Olympic 100m and 50m freestyle places.

"I will enjoy knowing I've qualified for three events."

Lowe, who had reclaimed her British record from Halsall in the heats, finished behind her rival in 58.27 to add a 100m butterly spot to her 200m butterfly place for Beijing.

Sixteen-year-old Ellen Gandy, from Beckenham, who had already qualified in the 200m butterfly, missed out in the 100m event but finished third with a personal best of 58.49.

Swimmers have to achieve the Olympic qualifying time in the heats and then need to finish in the top two in the final to earn selection.

In order to replicate the programme in Beijing, heats are swum in the evening with the finals the following morning.

City of Edinburgh swimmer Kris Gilchrist won the men's 200m breaststroke final to add a second event for Beijing after qualifying for the 100m breaststroke earlier in the week.

The job is done and I am now looking forward to the World Championships Thomas Haffield

"I felt really good last night and was really expecting to go under 2:10," he said.

"It was solid but I'm going to need to drop at least a second to be in the mix (for Beijing)."

Sheffield's James Kirton shrugged off his injury problems to finish second in 2:13.47 and book his Olympic place, with Loughborough's Craig Elliot third in 2:15.23.

Thomas Haffield, who had taken more than six seconds off his personal best to set a new Commonwealth record in the 400m individual medley heats, was again too good in the final.

Haffield, from Cardiff, could not improve on Thursday's time of 4:12.59 as he finished in 4:14.01, although both times are quicker than the efforts of world record holder Michael Phelps so far this season

Euan Dale (4:16.33) finished ahead of his Loughborough team-mate Joe Roebuck (4:18.05) to take the second Olympic spot.

"It is hard to go back-to-back 400m IM," said Haffield.

"I felt really tired out there today. I think that showed with the time, my legs just lacked energy they didn't give me the drive that I wanted.

"But the job is done at the trials and I am now looking forward to the World Championships next week."

Stockport's Michael Rock produced a storming finish to edge out Todd Cooper in the final of the men's 100m butterfly.

Cooper, from Stirling, had been fastest in the heats, but Rock turned the tables to win in 52.30. Cooper set a personal best of 52.33.

"All the work I've put in has come good," said Rock. "I knew I had to be in the race at 70m and then kick in as hard as I could."

Swansea's Matthew Bowe had made the Olympic qualifying time but missed out on Beijing as he was edged into third in 52.82.

Beijing qualifiers to date:
*Already nominated to Team GB by British Swimming

Men
*David Davies - 1500m
*Liam Tancock - 100m backstroke, 200m individual medley
Mark Foster - 50m freestyle
Gregor Tait - 100m backstroke, 200m backstroke
David Carry - 400m freestyle
Dean Milwain - 400m freestyle
James Goddard - 200m individual medley, 200m backstroke
Chris Cook - 100m breaststroke
Kristopher Gilchrist - 100m breaststroke, 200m breaststroke
Ross Davenport - 200m freestyle
Robbie Renwick - 200m freestyle
James Kirton - 200m breaststroke
Thomas Haffield - 400m individual medley
Euan Dale - 400m individual medley
Michael Rock - 100m butterfly
Todd Cooper - 100m butterfly

Women
*Kirsty Balfour - 200m breaststroke
Caitlin McClatchey - 100m freestyle
Fran Halsall - 100m freestyle, 50m freestyle, 100m butterfly
Julia Beckett - 100m freestyle (relay)
Jessica Sylvester - 100m freestyle (relay)
Jemma Lowe - 200m butterfly, 100m butterfly
Ellen Gandy - 200m butterfly
Rebecca Adlington - 400m freestyle
Jo Jackson - 400m freestyle
Gemma Spofforth - 100m backstroke
Lizzie Simmonds - 100m backstroke
Hannah Miley - 200m individual medley
Keri-Anne Payne - 200m individual medley
Kate Haywood - 100m breaststroke
Kirsty Balfour - 100m breaststroke