dipfan writes "In a re-run of the Lotus v Borland case that went to the US Supreme Court, the High Court in London has allowed a copyright infringement battle between two rival airline booking programs to go to trial, despite agreement by all sides that the two programs are written in different code. The airline Easyjet is being sued by software house Navitaire, creators of an online booking system called Openres, over Easyjet's booking system named eRes, developed by Bulletproof Technologies of California. Openres was written in Cobol, while eRes was written in Visual Basic, and the programs are also different in structure. But, according to the FT article: 'Parallels had been drawn between appropriating the "functional structure" of a computer system and commandeering the plot of a book, the judge noted.' If Navitaire wins, then any program that works like another program - even if written in different code - could be vulnerable. What happened to the principle that you can't copyright an idea? Bulletproof is counter-suing Navitaire in the district of Utah."