David Greene of Britain took the gold medal of the men\'s 400m hurdles in 48.26 seconds on Thursday night at the Daegu World Championships. Javier Culson of Puerto Rico took the silver with a time of 48.44 seconds. L.J. van Zyl of South Africa collected the bronze in 48.80sec. There was a false start in the final, but ended up with no hurdler disqualified. Angelo Taylor of the United States got a slight warning. Greene\'s mark, which was put at 48.27sec previously, is the slowest winning time ever for this event in the history of 13 IAAF World Championships since 1983. David Greene, at 25, whose person best of 2011 is 48.20, proved last year he could beat the very best by taking victory at the IAAF Continental Cup in Split in 47.88. This season he has been no less impressive with Diamond League wins in Lausanne and Birmingham. Culson, at 27, also took the silver medal of men\'s 400m hurdles at the Berlin World Championships in 2009. Van Zyl, fifth in the 2008 Beijing Olympics, had been in quite good shape before June this year. In February, the 26-year-old achieved his personal best of 47.66sec in South Africa\'s capital Pretoria. The mark is the fastest time among the eight hurdlers in the final, and one of the four fastest times in the world this year. Van Zyl had claimed victories in both the Rome and Doha legs of the Diamond League. In Rome, he clocked his third sub-48sec time of the season. Nonetheless, he has not dipped below 48 seconds after May and his form has waned in the past couple of months.