| Postcode | Country | County | Type | Status |
|---|---|---|---|---|
| England | Hertfordshire | Small | ||
| England | Hertfordshire | Large | Terminated December 1992 | |
| England | Hertfordshire | Small | ||
| England | Hertfordshire | Small | ||
| England | Hertfordshire | Small | ||
| England | Hertfordshire | Small | ||
| England | Hertfordshire | Small | ||
| England | Hertfordshire | Large | Terminated December 1990 | |
| England | Hertfordshire | Small | ||
| England | Hertfordshire | Small | ||
| England | Hertfordshire | Small | ||
| England | Hertfordshire | Small | ||
| England | Hertfordshire | Large | Terminated December 1995 | |
| England | Hertfordshire | Small | ||
| England | Hertfordshire | Large | Terminated June 1997 | |
| England | Hertfordshire | Large | Terminated July 1995 | |
| England | Hertfordshire | Large | Terminated December 1995 | |
| England | Hertfordshire | Large | Terminated July 2003 | |
| England | Hertfordshire | Large | Terminated December 1994 | |
| England | (pseudo) England (UA/MD/LB) | Large | Terminated July 1995 |