Four years ago Jackson won an Olympic bronze medal and just months later landed two silvers at the World Championships.

But her progress was interrupted by a rib injury caused by asthma, leaving her in doubt whether she would be able to compete at London 2012.

The 25-year-old qualified last month, however, and is ready to draw on the experience accumulated at three Games to drive her on.

Emotion

"I remember at my first Olympics I was the youngest person on the team and I'm now one of the oldest," she said.

"I've picked up a lot of experience over the past few years and that includes massive highs and lows.

"The fact that you've been through every emotion possible over the past few years definitely helps going into the Olympics.

"I remember at my first Olympics I was so nervous and didn't know what to expect. It felt very surreal.

"Now I know what to expect and what will happen at an Olympics.

"I've been to every competition in the calendar so I know all about the challenges. I just can't wait to swim now.

"This is a once in a lifetime opportunity and I'm so proud and privileged to be part of that."

Fantastic

Jackson will compete in the 400m freestyle at London 2012 and is relieved to have finally secured her place at the Games.

"It was fantastic to qualify. People were making such a big thing of the Olympics when I hadn't actually qualified," she said.

"I was a bit dubious of speaking about it too much, but now we can knuckle down and work on the training.

"To come away with a medal four years ago was fantastic. I'm training better than I have ever done before.

"A couple of years ago I went through a tough patch with my swimming, but now I'm really excited about racing.

"I feel in great shape. I'm doing a lot of metres in the pool and a lot of stuff on land, which is beneficial to what we do in the pool."