BRITISH SWIMMING CHAMPIONSHIPS
Venue: Pond's Forge, Sheffield
Date: Monday, 31 March to Sunday, 6 April
Coverage: BBC Sport website & BBC Radio 5 Live Sports Extra from 0955 BST
Tancock broke the record set by Thomas Rupprath
Exeter swimmer Liam Tancock set a new world 50m backstroke record of 24.47 seconds at the British Olympic trials in Sheffield on Wednesday.
Tancock obliterated German Thomas Rupprath's 2003 record of 24.80s.
"Everyone in the world has been queuing up for a world record," said Tancock, after becoming Britain's first swimming world record holder in 18 years.
"I decided to go for it a few weeks ago. I was feeling fast in training. I am really pleased," added Tancock.
Over the past two months 19 world records have fallen, with 18 of those, including Tancock's, set by swimmers wearing the Speedo LZR racer, provoking a debate within the sport.
Italy's Federica Pellegrini is the only swimmer not to have worn one of the suits in setting a world record during that period.
"I've been feeling in good shape - and now I'm looking forward to the next few months," said Tancock.
"It's a by-product of training for the 100m and it shows in the 50m. I wanted to come here and prove I am ready to race."
Adrian Moorhouse, who owned the 100m breaststroke mark in 1990, was the last British swimmer to hold a world record.
Earlier, Hannah Miley destroyed her own British record in the 200m individual medley, knocking almost three seconds off her personal best.
The 18-year-old won in two minutes 11.46 seconds and said: "I just got in and swam, the time was a bonus."
Second placed Keri-Anne Payne also dipped under the old national mark as she touched in two mins 11.46 secs.
"It's going to be a real bunfight for the final," said Miley. "Hopefully I can do it again tomorrow (Thursday). I just want to make the team."
Swimmers have to achieve the Olympic qualifying time set by British Swimming in the heats and then need to finish in the top two in the final for selection.
In order to replicate the programme in Beijing, heats are swum in the evening with the finals the following morning.
Terri Dunning and Lizzie Simmonds also achieved the qualifying time so the quartet will fight it out for two places tomorrow morning.