World records tumbled in the pool and on the cycling track on Thursday, as the first day of competition at the London Paralympics got under way and China won the Games’ first gold medal. At the Velodrome, seven-time Paralympic champion Sarah Storey  who won five swimming titles before taking two more when she switched to cycling in 2008  clocked a new world best 3min 32.170sec in the women’s C5 3km individual pursuit. The 34-year-old British cyclist’s time was quicker than the winner of the same event for non-disabled athletes at the UCI Track Cycling World Cup event held at the same venue in February. Australia’s women then posted a new world record in the C4 3km individual pursuit, with Susan Powell qualifying quickest in 4min 03.306sec to earn the right to meet US rider Megan Fisher to win gold. Queen Elizabeth II officially opened the Games at a showpiece ceremony on Wednesday involving more than 3,000 volunteer and professional performers.