China's 2004 Olympic 110m hurdles champion Liu Xiang announced his retirement on Sina Weibo, China's version of Twitter, on Tuesday (7).

With 200 days to go until the Chinese capital hosts the IAAF World Championships, Beijing 2015, seven leading athletes have been made ambassadors of the championships, which will run from 22-30 August.

It’s not often that four world record-holders in any given event are in the same room at the same time, but when it happens it is truly an extraordinary experience.

London, UK – Hurdlers Liu Xiang, Sally Pearson and Dai Greene met the press ahead of the Aviva London Grand Prix, the eighth stop on the Samsung Diamond League circuit, when all the talk was of that other London athletics meeting in three weeks’ time.

Liu Xiang is a virtual certainty to make China’s Olympic team, but he will carry the expectations of 1.3 billion people to the line in London 2012.