P & O Containers will start a new independent container service between the UK and North Europe and the East Mediterranean on January 1. Three vessels, each with a capacity of 538 20-ft containers, will operate on a 27-day cycle, sailing every nine days. Ports of call will be Tilbury, Rotterdam, Pireaus, Izmir, Thessaloniki and back to Tilbury. The company will also run a dedicated weekly feeder service between Pireaus and Istanbul. The new service will start with the sailing of Portland Bay from Tilbury on January 12. Texel Bay and Alum Bay will be inducted later. Lyme Bay will operate the feeder service. A P & O spokesman said the new service ''underlines our commitment to the trade''.