Robbie Williams has been banned from performing at a Dubai racecourse. Sheikh Mohammed bin Rashid Al Maktoum - the current ruler of Dubai - rejected Robbie's concert request because the 'Feel' singer terrified the sheikh's thoroughbred racehorses when he performed there last year. Dubai Racing Club chief Frank Gabriel said: "The concert affected the horses' state of mind and their performance. That will not and must not happen ever again."Sheikh Mohammed is a major international figure in the breeding and racing of thoroughbred racehorses. He hosts the annual Dubai World Cup, which is the world's richest series of horse races.Robbie was paid a staggering £1 million (US $2 million) to perform at a sell-out concert at the course in April 2006.The singer's follow-up show was set to be the biggest concert ever held in Dubai.Robbie isn't the only music act to have upset equine residents.In July, a Rolling Stones concert in Serbia was moved following fears the noise could distress horses who were housed in a nearby stable.Serbian animal rights activists protested over plans to sedate the 300 animals during the event at Belgrade's Hippodrome.The show was later moved to a public park in Belgrade.