Police evacuated 20'000 people from one of Britain's top racecourses yesterday after dissident Irish republicans were said to have telephoned with a car bomb warning. Police said a man claiming to represent the Continuity IRA had telephoned a Belfast media organisation to say a car bomb had been left at Kempton Park racecourse, south-west of London. We very much hope it will turn out to be a hoax. But we felt we were left with no option, Sue Ellen, managing director of United Racecourses, told reporters. The mass evacuation was ordered just after the running of the King George VI steeplechase, one of the biggest races in the British racing calendar. Ellen told reporters: We received a message from the police just before the King George VI steeplechase and they told us they had received a call warning there was a car bomb at Kempton Park. We had to decide whethere we thought this was real or whether it was a hoax but if there was a device, it was not due to go off for a period of time, she said. We ran the big race which was what everyone had come for and we felt this was the thing to do, she added.