According to the Postal Services Directive (PSD), EU member states must ensure that users enjoy the right to a universal service involving the permanent provision of a postal service of specified quality at all points in their territory at affordable prices for all. However, member states have a degree of flexibility in defining the precise details of the universal service obligation (USO) in their national laws and regulations.

The PSD further requires member states to ensure that the universal service provision evolves in response to the technical, economic and social environment and to the needs of users. A number of countries have therefore taken steps to reconsider the scope and features of their postal USO in light of the steady decline in letter volumes and shifting communication behaviours. 

Many modifications to the USO at national level are made through regulatory decisions and/or amendments to relevant secondary legislation. More fundamental changes to the rules affecting the postal sector are introduced through revisions to primary legislation.