A third Olympics beckons for David Carry, but he will have to conquer the nerves of a final trials show-down at the Ponds Forge Pool in Sheffield this week if he is to join the five Scots already in Team GB for London 2012.

With 38 swimmers having gained places at the first round of trials at the new Games pool in London in March, there are not too many up for grabs at the four-day ASA National Championships starting on Wednesday. Hannah Miley, Michael Jamieson, Robbie Renwick, Caitlin McClatchey and teenager Craig Benson are the Scots already assured of Olympic selection and Carry, Jak Scott, Craig McNally, Lucy Ellis and Lewis Smith are among those heading for Sheffield with the dream swishing around in their heads.

Carry, the double 2006 Commonwealth Games medallist, was unlucky not to secure his place at the first time of asking. In the 400m freestyle, he touched second behind Renwick, and the time of 3:48.36 was just fractions outside qualification. If no-one else goes faster this week and he has a time of 3:48.92 or better then all should be sweet.

"I have been thinking about making the London Olympics for years and years and it was so annoying to miss out by fractions in March," said the 30-year-old Aberdonian, who is will marry fiancée Keri-Anne Payne, an Olympic open water gold medal hopeful, just weeks after the Games. "But all is not lost and I have another chance this week."

Scott made his GB debut in the 4 x 200m freestyle relay squad at the World Championships in Shanghai last summer and he has a silver relay medal from the 2010 Commonwealth Games.

The Stirling youngster was just 14 when London was awarded the Games in 2005. "We were driving to France for a family holiday," he recalled. "We were just outside Carlisle when it was announced that London had won the 2012 Olympic bid. I remember all the cheering on the radio and it was exciting. But I never dreamed I could be a competitor."

Having finished fifth in the 200m freestyle relay at the first round of trials, he has a tentative grip on a relay squad place. He hopes to grasp it with both hands at Sheffield.

Ellis is another with a freestyle relay place in her sights, while the fact that no-one has made the time in the 200m backstroke opens the door for Warrender's McNally to make a late charge.

Smith, better known as a 400m medley man, has had a change in emphasis and will join Carry in the race for the second 400m freestyle relay spot.

Ten Scots made the Beijing Olympic team, and Ally Whike, Scotland's performance director, is delighted with the quality of this year's contribution. "The five who have made it so far are a mixture of experience and youth. It would be great if we could end up with seven or more on the final team."