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HMRC internal manual

VAT Clothing

The design test - is the article designed for young children?: Body Measurements

Additionally, you should refer to the list of body measurements in Notice714. If a garment has been designed for a person under 14 and the body measurements used are at or below those in the list of body measurements then you can zero rate the article irrespective of its measurement. This list is intended to take account of changes in fashion, for example, a trend towards baggy clothing may mean that garments exceed those in the table of maximum garment measurements, but are still designed to fit persons under the age of fourteen. However, zero-rating would not apply in such circumstances if the garments were also suitable for persons over the age of fourteen.