While most buyers of the UK's best selling car are swayed by its stylish looks and technology-laden interior, the Ford Fiesta hides an important secret under the skin.

At the heart of the Fiesta’s appeal is an advanced steel bodyshell which combines light weight with outstanding strength and durability.

Light weight means better fuel economy and performance, while the strength of the structure is reflected in the Fiesta’s five-star Euro NCAP safety rating.

To achieve this impressive combination, Ford engineers turned to new metals for the body.

Over 55% of the structure is made from ultra high strength steel – helping to make the Ford Fiesta 40kg lighter than the model it replaced.

Bernd Liesenfelder, Ford body engineering manager, said: "Small cars like the Fiesta need to be as light as possible without sacrificing any strength in a crash.

"By using these advanced new steels, we have been able to give Fiesta owners the protection of a robust safety cell, combined with excellent fuel economy from a lightweight body."

The Fiesta bodyshell features a range of different high-strength metals, including boron steel - one of the strongest weldable materials available.

Sophisticated computerised design tools allow Ford engineers to locate the high-strength steels exactly where they are required to provide maximum protection in a crash.

High-strength steels can be used more efficiently than normal steels without reducing strength, allowing components to be lighter.

This light weight helps to reduce fuel consumption and CO2 emissions across the Fiesta range, including for the exceptionally frugal ECOnetic model, which achieves combined fuel economy of 76.3mpg and 98g CO2/km emissions for road tax-exempt motoring.

(PR/GK)