A legal battle over patents for plastic nets may go to the House of Lords. In 1992 the High Court ruled that two nets patents held by PLG Research were invalid as no inventive step had been used to arrive at their design. But, last November the Court of Appeal held the nets were covered by patent protection and patent had been infringed. Now Ardon International, which was taken to court by PLG, is seeking to appeal. The Law Lords gave until 9 May for objections to be lodged.