Foxconn International Holdings, the world's largest contract manufacturer of mobile phones, must square off in court against BYD to defend claims that it conspired to cause harm to the mainland car and battery maker's business. In a decision handed down yesterday at the Court of First Instance, Justice Louis Chan Kong-yiu said BYD's plea 'should be allowed to develop and be decided by the trial judge who would be able to hear all the evidence of the parties'. The ruling marks the latest twist in the acrimonious and long-standing dispute between the two hi-tech companies, which have been in litigation, with suits and countersuits, in both Hong Kong and the mainland. In October 2007, three Foxconn units - Shenzhen Futaihong Precision Industry, Hong Fu Jin Precision Industry (Shenzhen) Co and Foxconn Precision Component (Beijing) Co - jointly brought action in Hong Kong against BYD and its six subsidiaries for breach of mainland law against unfair competition. That action followed a lawsuit filed in June that year by Foxconn against BYD in the Intermediate People's Court in Shenzhen, claiming BYD knowingly and intentionally procured confidential data from former employees. BYD, whose handset-manufacturing business directly competes against Foxconn, had been unsuccessfully sued before by Sony and Sanyo for patent infringement. 'We have a strong conviction to protect our intellectual property and trade secrets as well as customers' confidential information,' Foxconn International chairman and chief executive Samuel Chin Wai-leung said at that time. In response, BYD chairman Wang Chuanfu had said: 'Foxconn filed a lawsuit against us as they are too scared to see our strong growth.' In 2008, BYD failed to persuade the Hong Kong court that Foxconn's case be tried in its home base of Shenzhen. Justice Au Hing-cheung said that Shenzhen was not a preferable venue. Last year, BYD and its subsidiaries brought a counterclaim in Hong Kong against Foxconn International, its three subsidiaries and Taiwan-based parent Hon Hai Precision Industry, the world's largest contract electronics manufacturer. BYD, in which a unit of United States investor Warren Buffett's Berkshire Hathaway has a 10 per cent stake, said the Foxconn group had, since 2006 been unlawfully interfering with its business to damage the company. It claimed the Foxconn group 'embarked upon a course of conduct of procuring and using false and fabricated evidence, or evidence unlawfully obtained, to launch proceedings' against it. It was specifically claimed that Foxconn unit Hong Fu Jin in about May 2006 unlawfully detained a former BYD employee to obtain 'false evidence of misappropriation and disclosure of confidential information' to the car and battery maker. There was another allegation that Hong Fu Jin tried to coerce another former employee in October 2006 to make a false confession about securing Foxconn trade secrets. In July this year, Foxconn group lawyer Winston Poon sought to throw out BYD's claims. He described the accusations against his clients as 'immaterial' and a 'waste of the court's time and money'. Justice Chan yesterday dismissed Foxconn's motion to strike out BYD's counterclaim. 'Given the circumstances of the alleged detention, intimidation and aggressive interrogation' of the former BYD employee, Justice Chan said 'this issue should be for the trial judge'. Shares of Foxconn International fell 1.21 per cent to HK$5.72 yesterday. BYD's closing share price was unchanged at HK$44.65.