Olympian Sharron Davies has waded into the row on swimmer Lia Thomas by labelling a Labour MP's defence of her as disgraceful.
Lia became the first transgender woman to win an NCAA Division I title, which sparked fierce debate on both sides.
Rival Reka Gyorgy complained to the athletics association about its decision to let Lia race against "biological women".
But Labour equalities minister Charlotte Nichols leapt to the swimmer's defence and congratulated her on her achievement.
She wrote: "As a former competitive swimmer myself, indeed, I know full well how much training is required for a title like this.
Mar 19, 2022; Atlanta, Georgia, USA; Penn Quakers swimmer Lia Thomas on the pool deck at the NCAA Swimming & Diving Championships at Georgia Tech. Mandatory Credit: Brett Davis-USA TODAY Sports
Brett Davis
"Anyone trying to diminish Lia Thomas' achievement because of lazy transphobia should frankly pipe down.
"Huge congratulations to her."
Olympic silver medallist Sharron Davies blasted Ms Nichols' words, claiming she had a "total misunderstanding" of elite sport.
She wrote on Twitter: "Disgraceful abandonment of Women’s right to equal opportunities in sport, so disappointing from an MP supposedly representing females too I presume?
"A total misunderstanding of elite sport.
"I seriously question your understanding of high level performance competition/training."
Another added: "Is this for real? Your constituents are reading this."
"While one man claiming to be a former competitive swimmer wrote: "As a former competitive swimmer, how many elite races do you know of that have been won with a 38 second margin?
"You insult the dedication training and effort of female athletes by suggesting they might have won against someone who has gone through male puberty. Another vote lost."
Thomas's victory came after a civil rights complaint was submitted against the University of Pennsylvania for permitting her to compete on its swimming team.
Also brought up was Lia's ranking of 462nd when she competed in the male ranks.
