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Video - GB's Darren Kenny wins cycling gold on the opening day
Britain's cyclists won three gold medals on day one at the Paralympics.
Welshman Simon Richardson, 41, recorded a new LC3/4 1km time-trial world best to win Britain's first gold medal in one minute 14.936 seconds.
Scottish tandem cyclist Aileen McGlynn and her Welsh pilot Ellen Hunter lowered their world record to retain the B&VI 1-3 1km time trial title.
And Darren Kenny, 38, shattered his own CP3 world record by six seconds and later won the men's individual pursuit.
Kenny, from Dorset, who won two gold medals at the Athens Games four years ago, overtook his Spanish rival Javier Ochoa after just 1000 metres of the 3000m race as he set a new best of 3:36.875 secs to reach the final.
And in the final, Kenny, who suffers from cerebral palsy, again overtook his opponent, South Korea's Jin Yong-sik, after just 1000m to claim his third Paralympic title.
He said: "It all went according to plan, no problems at all.
"I'm overjoyed and relieved to get the gold - we've put a lot of work into it so it's just the relief that it's done."
Richardson, who competes in a class for riders with impairment in one lower limb who usually pedal with only one leg, or riders with disabilities affecting both legs, said he could not believe he had won the gold.
"I'm totally shocked," he said. "This is a completely unexpected gold medal. This race was really a warm up for the 3km, so I went into it thinking 'Whatever we get'."
Japan's Masaki Fujita finished second, more than 2.3 secs slower than Richardson, while 2004 champion Greg Ball of Australia took bronze with a world record for his LC4 class.
Richardson revealed his bike has been constructed using parts from previous British Olympic winners.
He said: "My bike is Jason Queally's frame and Chris Hoy's handlebars."
McGlynn, who is registered blind, powered to a new world record of 1:09.066 seconds with Hunter to retain the title they won four years ago in Athens.
"We're absolutely delighted to have broken the world record and the Paralympic record," said McGlynn.
"It was a hard ride but we knew we had it in us to do the time."