P&O Ferries signed a 360m Euros contract with Aker Yards (later renamed STX Europe) on 8 August 2008, for the two largest ferries ever to be constructed for the Dover-Calais service. These ships were being built with the intention of replacing the 1987 Townsend Thoresen ships the Pride of Dover and Pride of Calais which were become too small and too expensive to operate. The new ships were to enter service in January 2011 and September 2011.
The new ships were to be the largest and most modern on the Dover to Calais route, whilst not reducing the sailing time they were to set new standards onboard and were also being designed and built to comply with the Lloyds Register "Green Passport" which provides a comprehensive strategy for all the materials used within the ship. The ships, unlike those being replaced had the benefit of being designed on computer and through computer models they are designed to be environmentally friendly and fuel efficient. They are the first passenger ferries in the world to comply with the new International Maritime Organization "Safe Return to Port" requirements. These rules require that in the event of a ship becoming a casualty, basic services are provided to all persons on board and that certain systems remain operational for a safe return to port. Performance standards are stipulated for a wide range of ship systems including fire-fighting, power supply, propulsion, steering and navigation.
In addition the ships have the Lloyd's Register class notation of PSMR (propulsion and steering machinery redundancy) which will be assigned where the main propulsion and steering systems are configured to ensure that, in the event of equipment failure, the ship retains availability of propulsion power and manoeuvring capability to provide a safe return to port.
Whilst the news that two new ships will be built, with an option to build two more to the same design, was excellent news it did however lead naturally to the news that two of the oldest and most well known ships operating on the Dover to Calais service would be withdrawn. These being the 1987 built Pride of Dover and Pride of Calais, the last ships built for Townsend Thorsen and the most successful ships ever built for the route.
An interesting fact of the new ships, the three bow thrusters have the same amount of power as the main engines on the 1987 built Pride of Dover and Pride of Calais!!!
Shortly after entry into service serious vibrations problems were found on the Spirit of Britain which meant the ship operated on reduced power throughout its first year in service. As these were replicated on the Spirit of France, still under construction in Finland, the ship yard was able to see first hand the issues and as such the Spirit of France was delayed for several months whilst the issues were rectified, finally arriving in Dover at 11:00am on the 28th January 2012, just over 12 months after the Spirit of Britain. Upon entry to service the Spirit of France undertook the maiden voyage in 55 minutes between Dover and Calais pier heads.