We may be in the middle of most precipitous downturn since the oil crisis of the early 1970s, but European car makers have just received another mighty shock, albeit not unexpected.

The European Parliament has just passed legislation that will require the average CO2 emissions of a new car to be just 130g/km.

That’s a real-world 58mpg from a diesel engine and 52mpg from a petrol engine. Another 10g/km reduction will be achieved by using biofuels and tyre pressure monitors.

The plan will be phased in over the next six years, and it looks as if small companies such as Bentley and Ferrari are safe, though if they break through the 10,000 annual sales barrier, they will have to join Jaguar-Land Rover and Porsche in slashing CO2 emissions by 25 per cent on their 2007 average.

It’s not hard to imagine the average car being good for 120g/km by 2015 – the Ford Focus 1.6 diesel is already down to 119g/km.

But what about BMW and Mercedes? What about any car bigger than a Golf-class hatch? Even today’s best petrol-sipping ‘Blue Efficiency’ 1.6-litre C-class is still only good for 149g/km. Even the diesel version can only manage 134g/km.