Thompson finished fourth in the EAD 800m final

"It's sad but I won't be competing in four years," said the Cardiffian, 36.

"I'll be competing for the rest of this season, and I'll decide in September whether Beijing 2008 is realistic.

"It was always going to be difficult for me in the T54 category. Fourth is pretty good for me, but I felt I could have been better technically."

Canada's Chantal Petitclerc won the race in a new world record of 1min 48.98s, with Australia's Eliza Stankovic second and Diane Roy of Canada third.

I wouldn't have swapped my years competing for Wales for the world Tanni Grey Thompson

"Chantal was always going to be fast, but no-one expected a world record this early in the year," Thompson told BBC Sport Wales.

"She's been so strong for the last three years, none of us can touch her."

Thompson says that Team Wales have done her proud in Melbourne.

"We're only a small country, but everyone has competed so well," she said.

"I wouldn't have swapped my years with Wales for the world, it's been amazing."