A FORMER acting commissioner of the Royal Hongkong Police Force is to leave his Mediterranean retirement home next month to run the 100-strong security team guarding the troubled Macau Jockey Club. Eric Blackburn has been asked by Macau casino magnate Stanley Ho to take over as security controller. Mr Ho, also chairman of the Jockey Club, is believed to have faxed an ''invitation'' to the former Deputy Police Commissioner. Mr Blackburn's appointment follows a season in which Macau jockeys and trainers have been threatened and attacked in what is believed to have been intimidation attempts by a local ''mafia'' to ''fix'' races. Information and international affairs controller for the club, Paul Chan, confirmed the appointment and said Mr Blackburn would take up his position on August 1. Mr Chan said Mr Blackburn's appointment had nothing to do with the problems, in which at least two jockeys were forced to hide after being attacked and threatened. ''That should be taken as a single incident and not connected with the head of the security department,'' he said. The previous head of security, John Chau, another former police officer, left earlier this year. One regular Macau punter believed Mr Blackburn had been hired to solve the problems and give the club a clean public image. ''There is a major problem with hoodlums over there, and I think that is why Eric has been called in,'' the racing fan said. ''They want a gweilo in charge; a gweilo who can think like a Chinese and can speak Cantonese.'' Mr Blackburn is well connected in Hongkong and Macau, which will be useful in sorting out any problems at the club. He will be provided with a car, accommodation, access to the club's facilities, and what is believed to be a substantial remuneration. ''We provide senior officials in the club with certain fringe benefits,'' Mr Chan said. Mr Blackburn retired at the end of February 1988 when he was 55, and became an executive director of Hopewell Services and Agency Ltd., before leaving for Cyprus.