Meter Point Administration Number

A Meter Point Administration Number, also known as MPAN, Supply Number or S-Number, is a 21-digit reference used in Great Britain to uniquely identify electricity supply points such as individual domestic properties. The system was introduced in 1998 to aid creation of a competitive environment for electricity supply companies, and assists consumers to switch their supplier as well as simplifying administration.

Source: Wikipedia — Meter Point Administration Number (CC BY-SA 4.0)