The Goods Vehicles (Licensing of Operators) Act 1995 requires businesses using heavy goods vehicles over 3.5 tonnes to be licensed. This licence is called an Operator licence, also referred to as an O licence. It is the legal authority you need to operate goods vehicles in Great Britain and is issued by a traffic commissioner. An Operator licence allows you to operate vehicles, including trailer combinations, in Great Britain above 3.5 tonnes gross vehicle weight (gvw) that are used to carry goods.