The UK's Technology Strategy Board, with central and regional government support, funded the world's largest multi-site demonstration trial of ultra-low carbon passenger cars. 349 cars were deployed supported by the installation of approximately 500 electrical charging points. The trial has contributed to the UK Government's newly published ultra-low emission vehicle strategy. It has also helped vehicle manufacturers and energy suppliers understand how people use these cars and how they feel about them. Eight project teams comprising at least one vehicle manufacturer, an energy supplier, a local authority, infrastructure provider and a university have gained funding. The trial included two separate research activities: 1. Usage patterns - including time and duration of journeys, energy used and charging location. 2. User perception - questionnaires and interviews with users before, during and after the trail to help understand their feelings about the car and their behaviour with the car. The first 65 cars were handed over to users on 13th December 2009. By December 2011, 349 vehicles from 19 manufacturers had been deployed over a mix of private domestic, company pool or fleet vehicles. The vehicles have undertaken over 276,000 trips covering over 1,500,000 miles, and have charged over 51,000 times. The vehicle models included the plug-in electric Tata Indica, Mercedes Smart For Two, Nissan Leaf, Ford Transit Connect; BMW Mini-E, Mitsubishi i-MiEV, Allied conversions of the Peugeot Tepee MPVs; the hydrogen fuelled Microcab; and performance electric sports cars including the Ecotricity conversion of the Lotus Exige. The fleet also included plug-in versions of the diesel hybrid Land Rover Range-E and the petrol hybrid Toyota Prius. This paper provides details of the programme and results of the research to date, focusing especially on vehicle usage and perception data from 12 months of usage.