DAME Sarah Storey was unsuccessful in her effort to break the hour world record at the Olympic velodrome, but she did set a British and Paralympian C5 best.

The 11-time Paralympic champion took on Dutchwoman Leontien Zijlaard-van Moorsel's record of 46.065 kilometres, which was set in 2003.

Storey began well but had slipped off the pace by the halfway mark and never looked like pulling back the deficit. The 37-year-old, a former champion swimmer who switched to cycling in 2005, had covered 45.502km at the end of the hour.

There was no doubt she had put everything into her effort as she was helped off her bike and lay on the floor in obvious agony.

"It was definitely the hardest hour of my life," Storey said.

"I came in here hoping to go further than 46km, but to break the British record, I'm really chuffed. It's not as far as Leontien but to miss out to her is no bad thing."