Weights and measures

Enforcing weights and measures legislation


EU New Approach harmonised legislation sets out essential requirements which products must meet to benefit from free movement within in the EU. Products approved under New Approach legislation carry the CE marking, a declaration by the manufacturer that the product meets all the legal requirements. 

The Office for Product Safety and Standards has policy responsibility for the Measuring Instruments Directive and the Non-Automatic Weighing Instruments Directive. It has statutory duty under these directives to carry out market surveillance activities. This is to ensure instruments that do not comply with the provisions of the directive are neither placed on the market nor put into use.

Measuring Instruments Directive

The Measuring Instruments Directive (MID)  covers 10 categories of instruments. The UK regulates the following types; 

  • water meters
  • gas meters
  • active electrical energy meters
  • fuel dispensers
  • road tankers
  • automatic catchweighers
  • automatic gravimetric filling instruments
  • automatic discontinuous totalisers
  • automatic rail weighbridges
  • beltweighers
  • taximeters (responsibility of the Department for Transport)
  • material measures of length, capacity serving measures
  • exhaust gas analysers (responsibility of the Department for Transport)

The MID is implemented in the UK by the Measuring Instruments Regulations.

Non-Automatic Weighing Instruments Directive

The Non-Automatic Weighing Instruments Directive (NAWI)  covers instruments where an operator is involved in some form of the weighing process. The NAWI Directive is implemented in the UK by the Non-automatic Weighing Instruments Regulations. The scope of the Regulations covers a wide range of applications, for example:

  • scales used in a greengrocers
  • weighbridges
  • airport baggage weighers
  • baby-weighers


WELMEC is a European Administrative Cooperation made up of representative national authorities who are responsible for making sure legal metrology in the EU member states is consistent. They have also produced a guide which outlines the recommended approach to market surveillance (PDF, 229K). The Office for Product Safety and Standards follows this approach.

Local weights and measures authorities

Local weights and measures authorities are trading standards departments that deliver the local enforcement of most of the UK's weights and measures legislation. The Office for Product Safety and Standards works closely with them to promote consistency and best practice.

Assessing weights and measurements instruments

Notified bodies are third-party organisations chosen by the manufacturer to carry out conformity assessment of instruments under the MID and NAWI. This is to ensure instruments fulfil the directives essential requirements before being placed on the market. Conformity assessment can be inspection, quality assurance, type examination or design examination, or a combination of these.  Notified bodies are appointed by European Union member states and the Secretary of State in the UK.

To be impartial, it is essential that people who carry out conformity assessments are not the:

  • designer or anyone involved in the design
  • manufacturer
  • supplier
  • installer or involved in the maintenance of the instruments being inspected
  • user or authorised representative of the measuring instruments being inspected

You can find a notified body in the UK to help your business with conformity assessment.


Manufacturers, installers and repairers of weighing and measuring equipment approved by the Office for Product Safety & Standards can test, pass and verify their own work. They can also place their products on the market or return them to the market after a repair.
Approved verifiers are subject to regular audits . They are approved for a limited time and this can be taken away if the approved verifier breaks approval conditions.

Identify an approved verifier.

Manufacturers, installers and repairers who want to apply for approved verification status must provide documentation to prove they have an acceptable quality management system.

Enforcement resources

The Office for Product Safety & Standards carries out projects and produces reports and information to help local weights and measures trading standards departments enforce the legislation in the UK.

The weights and measures bulletins contain guidance for inspectors of weights and measures, approved verifiers and notified bodies on the interpretation of weights and measures legislation.

Stamp identification numbers are given to local weights and measures authorities and approved verifiers so that it is possible to identify which party approved a piece of weighing or measuring equipment. Download a list of national stamp numbers (XLS, 268K).

EEC stamp numbers are allocated to European weights and measures authorities to identify who has approved a piece of weighing or measuring equipment. They are the European equivalent of national stamp numbers. Download a list of EEC stamp numbers (DOC, 162K).

  • Office for Product Safety and Standards helpline
    0121 345 1200
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