Top 10 Detroit motor show cars - Mercedes E300 Hybrid

The Mercedes has been left behind by BMW's ultra-clean 520d Efficient Dynamics – so on the face of it, the E300 Hybrid could be a rival for the frugal 5 Series.

In fact, the E300 is unlikely to undermine the four-cylinder diesel E-Classes, because it's expected to carry a price premium over the E200, E220 and E250 models. Instead we're looking at an alternative to the E350 CDI, and a potentially worthwhile one at that.

The E300 blends Merc's 2.2-litre, 201bhp four-cylinder turbodiesel with a seven-speed automatic transmission and an integrated electric motor. It's capable of 67mpg, Merc says, and will emit just 109g/km of CO2 – that's the same figure as the 520d Efficient Dynamics, although the E300 does it with an auto 'box. BMW's star uses a six-speed manual transmission. The E300's performance seems strong, too; it'll crack 150mph and reach 62mph in 7.5 seconds.

It's due on sale in July, and is expected to cost around £38,000. That's almost £10k more than an E250, but crucially, around the same as a well-specced E350 CDI. Given that the six-cylinder diesel model emits 162g/km of CO2, the E300 Hybrid is going to look a strong proposition against it.