The Oscar Pistorius row has been reignited amid fresh allegations by the South African team that athletes were changing blades between races.

The International Paralympic Committee (IPC) received a letter on Tuesday claiming competitors had been breaking rules by altering prosthetic legs between qualifiers and finals.

Blades are measured between races and it is illegal under Paralympic rules to switch blades during a competition.

Pistorius sparked controversy with angry comments he made after losing out on gold in the 200 metres, claiming Alan Oliveira's use of longer blades gave him an unfair advantage.

Craig Spence from the IPC said: "When we put that allegation to the coaches there was a look of shock to be honest, because running on different size prostheses or swapping them for races is extremely difficult to do for an athlete. There is no evidence that any athlete competed on different size running blades.

"Unless the South Africans can come to us with some evidence that proves otherwise, it's something that we won't continue investigating."

Meanwhile Lord Coe, chairman of the London 2012 Organising Committee, has defended the decision to invite politicians to medal ceremonies. During Prime Minister's Questions, Labour leader Ed Miliband said of the cacophony of boos which greeted George Osborne: "The Paralympic crowd spoke for Britain."

But for ParalympicsGB, the gold medal joy continued unabated as super cyclist Sarah Storey, 34, won her third title of the games.

She added to her two gold medals won in the 500m time trial and pursuit in the velodrome by winning the road race time trial at Brands Hatch in Kent.

Another win on Thursday and the swimmer-turned-cyclist, who has a partly formed left hand, will equal Baroness Tanni Grey-Thompson's British female record of 11 Paralympic gold medals.