A survey of children's body shapes in the UK has found that the waist measurement of both boys and girls is around 10cm bigger than it was 20 years ago - providing retailers with new data to create better fitting clothes.

The study carried out by Shape GB, which is part sponsored by high street clothing retailers including Next, George at Asda, Monsoon and Shop Direct Group, used 3D body scanners to measure 2,500 children aged 4-17 across the country.

Its findings show that the height, size and shape of children has increased in the two decades since the British Standard measurements for children's clothing was introduced in 1990. This was in turn developed from a set of measurements collected in 1978.

The new findings show an average 11-year-old girl now has a chest measurement of 78.4cm (7cm wider than it was 20 years ago), with a waist of 70.2cm (+10cm) and hips of 81.2cm (+4cm). But her height has gone up by just 2.7cm.

For boys of the same age, height has increased to 148.2cm (up by 3.6cm on 1990's data), with a chest measurement of 78.5cm (+10cm), waist of 70cm (+8.5cm) and hips of 80.2cm (+7cm).

Significantly, while many retailers may assume that boys and girls have the same body shape up to the age of seven, the results show changes in body shape between boys and girls occur at a much earlier age.

The data also suggests that retailers need to reflect increases in height in their labelling, as many currently label a five-year-old boy as being an average height of 110cm - when in fact he is 115cm.

Because of a lack of up-to-date data, many clothing retailers have been forced to develop their own measurements based on customer feedback and internal fittings, but the Shape GB figures provide the industry with a new benchmark.

A spokesperson for Next confirms the size survey provides new information on shape, which cannot be collected manually, adding: "We are now able to use this information for sizing and labelling to ensure the best possible fit for children and their parents."

While Paul Wright, garment technical manager at George at Asda adds: "Our customers have told us they often judge the quality of clothing on whether it's a perfect fit.

"Having the ability to measure bodies using a 3D scanner and closely monitor the changing shapes of UK children will provide us with everything we need to tweak our sizes and give parents exactly what they are looking for."

Other retailers are also able to obtain the data, which may ultimately create and harmonise measurement standards, both in the UK and in Europe.