Whatever you make of the Toyota Prius, the plug-in version certainly has all the right statistics to put clear water between it and the slew of CO₂-efficient diesels on the market. Toyota has announced that a 600-car trial of the plug-in hybrid hatch will begin in the middle of 2010, with 20 of those coming to the UK.

The plug-in version has ditched the standard car's nickel metal hydride batteries and replaced them with the lithium ion units found in most new electric cars, which are more energy dense and therefore give a greater electric-only range.

Like the freshly announced BMW 1 Series ActiveE, trialling the plug-in hybrid - rather than putting it on general sale - will allow its maker to gather real world usage data that should prove helpful in facilitating an electric charging infrastructure somewhere down the line, as we look to reduce our dependency on oil.

The plug-in Prius is powered by a 98bhp 1.8-litre petrol engine linked to an 81bhp electric motor, which can be fully charged in around three hours from a normal power supply. It spits out only 59g/km of CO₂ on the combined test cycle too (as compared to 89g/km for the normal car), which comes about because of the circa 12.5-mile electric range it offers, at speeds of up to 62mph. The normal Prius musters just over a mile's worth of electric power - all below 30mph - before switching to petrol power.

We don't know what the lease cost will be to the 20 UK customers taking part, but we don't expect it to be cheap.