A Stock Exchange Daily Official List (SEDOL) code is one of many codes used to identify UK listed securities.
A SEDOL code is a seven digit number. A security's SEDOL is the basis of its ISIN. The ISIN is the SEDOL plus the prefix "GB00" with a single check digit suffixed.
SEDOL codes are not memorable, and therefore more commonly used by automated systems than by people. TIDM codes are generally easier to remember. The main advantage of SEDOL codes is their simple relationship with ISINs.