A Euro 6 compliant car will offer reduced levels of emissions compared to a Euro 5 compliant car, with harmful particulates generally the element that sees the most reduction.

Aside from this, the main reason for buying a Euro 6 car is that it will be exempt from London's ULEZ and clean air zones, so you will not have to pay a charge - although you should always check online before entering a zone such as this. However, if driving in these zones is not a typical journey for you, then there will be no real cost saving.

Generally speaking it makes sense to go for the newest and cleanest car you can afford, but the advantages of choosing a Euro 6 version of a car that is also available as Euro 5 are relatively small.