Our latest photos from the Nurburgring reveal the 2011 Vauxhall Astra going through high-speed testing at the famous German circuit. This disguised prototype is underpinned by General Motor’s new global Delta platform, which is also used as a base for the electric-hybrid Chevrolet Volt concept car. This commonality makes it very likely that the next-generation Astra will offer a version of the Chevrolet’s low-emissions E-Flex powertrain, possibly combined with the familiar 1.3 CDTi diesel engine. This could make it the greenest vehicle in its class, with Prius-beating CO2 emissions.As for conventional engines, like the one powering this test mule, we can also expect a range of new high-efficiency turbocharged petrol engines along with some familiar diesel powerplants from the rest of the Astra range.Despite the prototype’s presence at the Nurburgring, there is no evidence yet of any high-performance derivatives of the new car. Vauxhall insiders have previously indicated that the range-topping VXR will not be replaced by a directly comparable model, and that future fast Astras will feature the same fuel-saving technology as the rest of the range.Click here to read our drive of the 1.4-litre turbocharged engine that will feature in the next generation Astra.