British Swimming Championships 2010
Dates: 29 March-3 April Venue: Ponds Forge, Sheffield
Live on BBC Radio 5 live sports extra, highlights on this website
Highlights - GB Swimming Championships - day one
Double Olympic gold medallist Rebecca Adlington held off teenager Jazmin Carlin to win the women's 200m freestyle at the British Championships.
Adlington won in a time of one minute 57.87 seconds ahead of Carlin's 1:58.51 with Jo Jackson third in Sheffield.
"I was really pleased with that, especially without the swimsuits and everything," said Adlington, referring to hi-tech suits banned since January.
This week's races serve as trials for the Commonwealth Games in October.
Carlin has been putting pressure on Adlington and world silver medallist Jackson in the women's freestyle events this year, winning over the 200m and 800m distances at the Great Britain v Germany meet in Swansea last month.
But Adlington had the beating of the 19-year-old this time around, while Jackson, who has suffered increasingly severe asthma over the winter months, appeared to struggle.
I am so glad I have guaranteed my Commonwealth place, and the rest of the week I can just focus on good racing again
Jackson, 23, looked to have trouble breathing as she left the pool following her final, propping herself up against the wall, having set a time of 1:58.93 behind Carlin.
"Jo's had a catalogue of problems over the winter, so I actually think that's a good performance for her," said her coach, Kevin Renshaw.
"Her asthma has been out of control - that cold snap went on forever and she never really got over that."
Renshaw confirmed that Jackson's bid for special drugs to tackle the condition, at a cost of thousands of pounds, had not yet succeeded, adding: "We're still waiting to hear back.
"It has to go through her Primary Care Trust up in Richmond, North Yorkshire, but it's taking its course now."
Meanwhile, Adlington declared herself happy with her winning time.
"I haven't really hit one minute 56 seconds since Olympic trials but, with this suit, tonight's time is decent enough," said the 21-year-old, who set her personal best of 1:56.66 at British Championships two years ago, ahead of victory in the 400m and 800m freestyle at the 2008 Beijing Games.
Monday: Women's 200m freestyle - Adlington victorious over Carlin
Tuesday: Tancock in men's 50m backstroke
Wednesday: Spofforth v Simmonds in women's 100m back, Halsall in women's 100m free
Thursday: Adlington, Carlin and Jackson round two in women's 800m free
Friday: Biggest night of the meet with most top GB swimmers competing
Saturday: Hannah Miley (women's 400m IM) and David Davies (men's 1500m free) in action
Adlington, who failed to qualify for the Commonwealth Games in Melbourne four years ago, added: "That is why it is so important to me to make it, not making it last time.
"I can remember coming out of the swim and everyone on poolside turning the other way because they didn't know what to say to me because I was just in tears.
"I am so glad I have guaranteed my place and the rest of the week I can just focus on good racing again."
The trio of Adlington, Carlin and Jackson are expected to clash twice more at this week's trials, in the finals of the 800m free on Thursday and 400m free on Friday.
The ultra-fast, non-textile swimsuits that became the focus of much of 2009's competitive swimming have been banned since 1 January this year, restoring swimmers to textile-based suits.
"This event is a little more unknown than our swimmers are used to because it will be their first chance to get a peak performance with the new suit rule," said British head coach Dennis Pursley before the trials began.
Scotland's Robbie Renwick won the men's 400m freestyle final, edging out David Carry by a fifth of a second in a time of 3:50.32.
Welshman David Davies finished ninth in the 10-man field, a full 14 seconds outside his personal best.
GB swimming stars aim for Delhi
"It's been a tough day at the office. I really got up for it tonight, I did my normal routine and tried to give it a good go, and it just wasn't there," he told BBC Radio 5 live sports extra.
"I've been in the British team for six years and luckily enough I've managed to be pretty much on form all the time, so this has been a new experience for me, getting beat by 10 guys in a British field."
England's Aimee Willmott ran Scot Hannah Miley close in the women's 200m individual medley, knocking a second and a half off her personal best to post a time of 2:14.25, just behind Miley's 2:12.32, to reach the Commonwealth Games.
Michael Rock, as expected, won the men's 200m fly final, but Rock slowed in the closing stages and his time of 1:56.86 was only just inside the 1:57.29 set by second-placed Roberto Pavoni.
Eleanor Simmonds then racked up 1056 points to win the women's multi-disability (MD) 400m final in a time of 5:35.16.
There were wins in the men's MD 400m freestyle for Jonathan Fox, plus Benjamin Procter in the men's MD 200m freestyle and Natalie Massey in the women's equivalent.
As trials continue, Gemma Spofforth, 100m backstroke world champion and world record holder, is expected to face a straight fight with close friend Lizzie Simmonds in that event's final on Wednesday, while the pair should also clash in the 200m backstroke on Friday.
Fran Halsall, who excelled at December's Duel in the Pool between a European team and the United States, winning three golds, is the woman to beat in the 100m free on Wednesday.
But Halsall left the pool shaking her head in dismay after her eighth-fastest time of 2:01.45 in Monday's 200m freestyle final - "thank God that's over with, now to the main events,"
she later wrote
on micro-blogging service Twitter.
The qualifying procedure for the Commonwealths, to be held in India, differs according to nation.
Swimmers winning finals in Sheffield will almost certainly appear at October's Games in Delhi, but the selection process for the Commonwealths will be completed by the European Championships and individual
English, Welsh and Scottish national trials
at different dates in the summer.
applies in Northern Ireland.