Trials of the first plug-in hybrid car introduced by a mainstream carmaker have begun.

EDF Energy and Toyota have teamed up to test – in reral world fleet conditions - a new plug-in hybrid vehicle (PHV) over the coming year.

The right-hand drive car will form part of EDF Energy’s company fleet and will be tested by employees under every-day driving conditions.

Toyota said the fleet trials are designed to evaluate vehicle performance within an urban environment, vehicle infrastructure requirements, and driver behaviours and expectations.

PHV technology is the next stage of hybrid technology and benefits from being able to be recharged from a standard electrical plug or a new generation of public charging stations in car parks and other convenient points.

EDF is using a new charging and invoicing system that is incorporated into the PHV.

This system is compatible with the first of 40 charging posts in the UK.

For short distances, PHV can be driven as an electric vehicle, resulting in a silent, zero emissions drive.

For longer distances, PHV works as a conventional hybrid vehicle.

Toyota hopes the PHV will bring “unsurpassed fuel efficiency and therefore record low emissions”.

Early test results indicate that fuel efficiency is significantly higher than current Prius.

For example, for low-speed journeys, PHV consumes roughly 60% less fuel than a Prius.

One of the research objectives is to confirm such PHV performance.

“This represents a step change towards acceptance of electricity in combination with hybrid technology as a viable and sustainable transport solution,” said Koei Saga, managing officer in charge of hybrid system development at Toyota.

The tests also aim at understanding consumers' acceptance of the new technology, as a preparation to broader commercialisation in the future.

Toyota has already confirmed that it will sell lithium-ion battery-equipped PHVs to fleet customers in Europe and other regions by the end of 2009.

“I am pleased to see industry pulling together to work on diversifying energy use and cutting global carbon emissions,” said John Hutton, the secretary of state for Business, Enterprise and Regulatory Reform.

“This trial will provide an invaluable insight into the future development of UK electric and plug-in hybrid vehicles.”