The data contained in these tables are produced from a snapshot of the Inter Departmental Business Register (IDBR) taken in March each year.
The main administrative sources for the IDBR are VAT trader and PAYE employer information passed to the ONS by HM Revenue & Customs under the Value Added Tax Act 1994 for VAT traders and the Finance Act 1969 for PAYE employers; details of incorporated businesses are also passed to ONS by Companies House.
A group of legal units under common ownership is called an Enterprise Group.
An Enterprise is the smallest combination of legal units (generally based on VAT and/or PAYE records) which has a certain degree of autonomy within an Enterprise Group.
An individual site (for example a factory or shop) in an enterprise is called a local unit.