Rebecca Adlington set the early pace at the British Gas ASA National Championships in Sheffield.
Final 14 places up for grabs at four-day event in Sheffield
Double Olympic champion Rebecca Adlington set the early pace at the British Gas ASA National Championships in Sheffield.
The 23-year-old from Mansfield is swimming the 200 metres and 800m freestyle at Ponds Forge, her final competition before the Olympics.
Adlington qualified for the Great Britain team in the 400m and 800m at the first stage of trials at the Aquatics Centre in March but there are still two spots up for grabs on the 4x200m relay.
The Nova Centurion swimmer led Wednesday morning's heats in one minute 59.47 seconds ahead of Rebecca Turner, the City of Sheffield swimmer who has already made the Olympic team in the individual event.
Jaz Carlin, part of the bronze medal winning relay squad at the 2009 World Championships, will hope to be among the contenders for the remaining slot alongside Turner.
The Swansea ITC swimmer has been affected by glandular fever while former Commonwealth champion Caitlin McClatchey has been forced to withdraw because of a chest infection.
With 38 having already been selected for Team GB at the first trials, the four-day event in Sheffield represents a chance for 14 more spots to be booked.
However, even victory here inside the FINA 'A' time does not guarantee selection. Instead, if a swimmer who has already qualified for London swam faster in the final at the Aquatics Centre - while matching the criteria - then they will be selected.
There is one spot left in the men's 400m freestyle alongside Robbie Renwick.
Alfie Howes headed the heats into tonight's final in 3:55.32 with former Commonwealth champion David Carry and David Davies, twice an Olympic bronze medallist, also through.
Potential
City of Sheffield's Matthew Johnson has undoubted potential having won four golds and a silver at last year's European Youth Olympic festival.
While there are no 200m butterfly berths remaining, the 17-year-old is surely one for the future and today he headed the heats in 2:01.96.
Norway's Aleksander Hetland heads the 100m breaststroke, the same event in which countryman Alexander Dale Oen was world champion in 2011 before he died at the end of April.
Andrew Willis was fastest Briton with a slot having become available after Daniel Sliwinski's withdrawal following injury.
Former European silver medallist Lizzie Simmonds was quickest into the 100m backstroke final although Gemma Spofforth and Georgia Davies have already filled the GB slots in that event.
Siobhan-Marie O'Connor, so disappointed not to have made the team in the 200m individual medley in March, heads the qualifiers into tonight's final in 2:16.08 with Jessica Sylvester leading the 100m butterfly (59.78).
In non-Olympic events, Luke Wood was fastest in the 50m backstroke (26.11) with Kathryn Johnstone heading the 50m breaststroke (31.78).
