Originally written for Professional Manager

Attention has been slowly but surely turning towards diesel cars, as European capitals including London register worrying levels of particulates in the atmosphere. The reason is fairly simple. While diesels are heralded for their low levels of carbon dioxide – at least compared to petrol – they emit other nasties such as particulate matter, plus nitrogen and suplhur dioxides that are bad news for those suffering from respiratory illnesses such as asthma.

The question is, having incentivised the take-up of diesel engines through attractive tax rates for fleet and business users in an attempt to reduce CO2 emissions – diesel and petrol sales for new cars are close to parity these days – will the EU now legislate to punish diesel drivers?

Not likely. The vast amounts of cash tied up in creating more efficient diesel technology have driven down CO2 emissions and scrubbed a lot of the nasties in more advanced catalytic converters, virtually eliminate turbo-lag and made driving an oil-burner as refined as a petrol. As such the car industry – not to mention the oil industry – would view that very dimly.

There’s another problem. Homologation – a posh word for standardisation – means that all emissions tests run in laboratories to ensure a level playing field. But – as a result – the figures bear little similarity to the reality. For the same reason you will rarely achieve anything like the official fuel economy on any car. The EU has recently realised that not only are its emissions figures for diesel pollutants wrong, they’re so wrong that current cars could never hit modern pollution targets. This means there’s a very real possibility that, despite recognising the danger to public health posed by diesel fumes, emissions targets could increase, rather than decrease before 2020.

Confused? Join the club. My advice is not to worry if you’re considering buying a diesel – or even a fleet of them, as emissions targets are unlikely to affect you anytime soon. But do service diesels properly, make sure they get regular long runs at motorway speeds to burn off nasties and ensure drivers understand the benefits of eco-driving. Diesels may be complicated machines, but they’re still machines. As ever, it’s how we use them that counts.