select entry in Code column to view full DE allocations in that range
| Code | DEF | Operator | Use | Notes |
| 1700 | Rothesay | |||
| 1701 | Geographic - unassigned | |||
| 1702 | Southend-on-Sea | |||
| 1703 | Geographic - unassigned (formerly Southampton) | |||
| 1704 | Southport | |||
| 1705 | Geographic - unassigned (formerly Portsmouth) | |||
| 1706 | Rochdale | |||
| 1707 | Welwyn Garden City | |||
| 1708 | Romford | |||
| 1709 | Rotherham | |||
| 1710, 1711 | Geographic - unassigned (formerly London Inner Area, National Dialling) | |||
| 1712, 1713, 1714, 1715, 1716, 1717, 1718, 1719 | Geographic - unassigned (formerly London Inner Area) | |||
| 1720 | Isles of Scilly | |||
| 1721 | Peebles | |||
| 1722 | Salisbury | |||
| 1723 | Scarborough | |||
| 1724 | Scunthorpe | |||
| 1725 | Rockbourne | |||
| 1726 | St Austell | |||
| 1727 | St Albans | |||
| 1728 | Saxmundham | |||
| 1729 | Settle | |||
| 1730 | Petersfield | |||
| 1731 | Geographic - unassigned | |||
| 1732 | Sevenoaks | |||
| 1733 | Peterborough | |||
| 1734 | Geographic - unassigned (formerly Reading) | |||
| 1735 | Geographic - unassigned | |||
| 1736 | Penzance | |||
| 1737 | Redhill | |||
| 1738 | Perth | |||
| 1739 | Geographic - unassigned | |||
| 1740 | Sedgefield | |||
| 1741, 1742 | Geographic - unassigned | |||
| 1743 | Shrewsbury | |||
| 1744 | St Helens | |||
| 1745 | Rhyl | |||
| 1746 | Bridgnorth | |||
| 1747 | Shaftesbury | |||
| 1748 | Richmond | |||
| 1749 | Shepton Mallet | |||
| 1750 | Selkirk | |||
| 1751 | Pickering | |||
| 1752 | Plymouth | |||
| 1753 | Slough | |||
| 1754 | Skegness | |||
| 1755 | Geographic - unassigned | |||
| 1756 | Skipton | |||
| 1757 | Selby | |||
| 1758 | Pwllheli | |||
| 1759 | Pocklington | |||
| 1760 | Swaffham | |||
| 1761 | Temple Cloud | |||
| 1762 | Geographic - unassigned (formerly Portadown) | |||
| 1763 | Royston | |||
| 1764 | Crieff | |||
| 1765 | Ripon | |||
| 1766 | Porthmadog | |||
| 1767 | Sandy | |||
| 1768 | 0&1 | Penrith National Dialling | 4 Digit Code Area | |
| 1768 | 2 | Penrith | 4 Digit Code Area | |
| 1768 | 3 | Appleby | 5 Digit Code Area | |
| 1768 | 4 | Pooley Bridge | 5 Digit Code Area | |
| 1768 | 5&6 | Penrith | 4 Digit Code Area | |
| 1768 | 7 | Keswick | 5 Digit Code Area | |
| 1768 | 8&9 | Penrith | 4 Digit Code Area | |
| 1769 | South Molton | |||
| 1770 | Isle of Arran | |||
| 1771 | Maud | |||
| 1772 | Preston | |||
| 1773 | Ripley | |||
| 1774 | Geographic - unassigned | |||
| 1775 | Spalding | |||
| 1776 | Stranraer | |||
| 1777 | Retford | |||
| 1778 | Bourne | |||
| 1779 | Peterhead | |||
| 1780 | Stamford | |||
| 1781 | Geographic - unassigned | |||
| 1782 | Stoke-on-Trent | |||
| 1783 | Geographic - unassigned | |||
| 1784 | Staines | |||
| 1785 | Stafford | |||
| 1786 | Stirling | |||
| 1787 | Sudbury | |||
| 1788 | Rugby | |||
| 1789 | Stratford-upon-Avon | |||
| 1790 | Spilsby | |||
| 1791 | Geographic - unassigned | |||
| 1792 | Swansea | |||
| 1793 | Swindon | |||
| 1794 | Romsey | |||
| 1795 | Sittingbourne | |||
| 1796 | Pitlochry | |||
| 1797 | Rye | |||
| 1798 | Pulborough | |||
| 1799 | Saffron Walden |