The trainer of beaten Dubai World Cup favourite Forever Young has claimed his horse was kept in a dark room for 40 minutes moments before the $12 million race, as he raised concerns over the drug testing procedure at Meydan. Yoshito Yahagi posted an open letter to the Emirates Racing Authority (ERA) on X, in which he outlined the timeline of events before the race that left the two-time Group 1 winner "considerably exhausted" before being sent off 4-9 and finishing third in one of the world's richest races. The Japanese trainer detailed that this year's Saudi Cup winner was kept in a pitch-black testing unit with ERA staff each following different procedures. Forever Young failed to urinate during this time and it led to a rushed race preparation to groom, tack and saddle him, leaving the colt distressed before the race. The trainer also said Forever Young was then not subject to a post-race test after finishing third, collecting almost £1 million in prize-money, as he requested an apology and clarification on the events. The ERA, however, said in a response that a sample was taken and the sampling area was "well-lit" and the timing was 26 minutes. Yahagi demanded action to be taken to prevent a repeat as well as a response because the race was closely followed in Japan, with the Japanese Racing Authority opening its own betting market on it. Yahagi said he felt obliged to request transparency for the fans of the sport, whom he described as "invaluable". Yoshito Yahagi: one of Japan's biggest trainers Credit: Edward Whitaker (racingpost.com/photos) In the post, Yahagi wrote: "I fully understand that it's my duty and obligation to abide by the rules and regulations set by a racing jurisdiction. Having said that, though, is it clearly stated in the ERA rules of racing that you will keep a horse inside a pitch-black room for approximately 40 minutes? Not to mention, the overwhelming favourite in the highlight race of your racing calendar, to collect a urine sample? "I had instructed my staff to be prepared if they were instructed by the ERA at the receiving barn. However, you were unable to collect any urine and the process was not followed up with a blood sample or any other possible method to prove that my horse was clean. In the end, you were not able to collect any evidence to protect the integrity of your racing. "I'm left having to wonder, for whom and for what were those 40 minutes that took so much out of Forever Young. The tragedy is that the biggest burden of this whole process went on the shoulders of one racehorse and, as a trainer responsible for an entrusted horse, not only do I feel truly regrettable of this situation, but I am also left having to question and hold strong doubts about the entire process and its purpose." Yahagi shared a response from David Craig, the ERA's head of equine health and welfare, on X in which he claimed the length of the testing procedure was 26 minutes rather than 40 and that the sampling box was well-lit and air-conditioned. Craig also revealed another horse had spent 35 minutes in a sampling area but won, and said that Forever Young was one of the seven horses to provide a sample from nine selected. Craig also said the comments had "prompted" the ERA to review its process and is considering introducing measures such as a maximum waiting time for pre-race urine collection as well as better communication and requesting horses to arrive earlier on major racedays. Read these next: 'Pressure? It's brilliant!' - Kieran Shoemark can't wait for date with destiny on Field Of Gold 'We need to try to get a Group 1' - Dancing Gemini takes another step forward with emphatic success Looking for free bets? Racing Post have got the best offers, all in one place. Visit racingpost.com/freebets to find out more.