Mark Foster today refused to rule out extending his extraordinary career until the London Olympics, when he will be 42.

The veteran swimmer, 38, will be competing in his fifth Games in Beijing after Seoul, Barcelona, Atlanta and Sydney and is by far the oldest member of Great Britain's aquatics squad.

But, having previously retired two years ago only to rethink his decision and qualify for the 50 metres freestyle, Foster claims 2012 is not out of the question.

He said: "This may be my last Olympics but I never say never. I am not looking at London in the slightest. It is a question of getting through this one and then there are some other things to do at home. After that, we will see. Who knows? In four years I might make another comeback.

"I am as good as I ever have been. When I came second in the world short course championships in Manchester [in April] that was just nought point one of a second off my best time."

Foster is yet to win an Olympic medal and, given the level of competition in his sprint event, he is keen to dampen expectations.

He said: "My expectations would be first of all to make the top 16. Then, if I can through to the semis and make the final anything can happen."

Meanwhile, fellow swimmer James Kirton faces a battle to be fit in time to take part in the 200m breaststroke after suffering a hernia injury.

Heats for the event take place on Tuesday and national performance director Michael Scott is hopeful the 23-year-old will recover in time.

Scott said: "James has a sporting hernia injury which the medical team and coaches have been working on.

"He's well in the road to recovery and hopefully in the next few days he will be ready."