Battle commenced in the High Court Friday between Plessey Co Plc and GEC Plc over Plessey’s contention that by conditionally agreeing to sell shares in GEC Plessey Telecommunications to Siemens AG, GEC was in breach of the agreements under which the joint venture was established: GEC issued proceedings in the Chancery Division of the High Court, asking it to rule on the validity of Plessey’s notice demanding that the clause in the agreement should now be invoked, and both sides are asking the court to set a hearing as soon as possible.