| Postcode | Country | County | Type | Status |
|---|---|---|---|---|
| England | Hertfordshire | Large | Terminated December 1998 | |
| England | Hertfordshire | Large | Terminated February 2017 | |
| England | Hertfordshire | Small | ||
| England | Hertfordshire | Small | Terminated December 2002 | |
| England | Hertfordshire | Small | ||
| England | Hertfordshire | Small | ||
| England | Hertfordshire | Small | ||
| England | Hertfordshire | Small | ||
| 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 | Large | Terminated December 1981 | |
| England | Hertfordshire | Small | ||
| England | Hertfordshire | Small | ||
| England | Hertfordshire | Small | ||
| England | Hertfordshire | Small |