16/07/2026
Ever wondered why all our A roads start with a ‘2’?
Danny: Thanks to Bill Plant for this.
Did You Know…? 🤔
Ever wondered why the A23 is called the A23… or why the A27 isn’t just a random number?
It all starts with the single-digit A roads!
The UK is divided into 9 road zones, with each zone sitting between two of the major single-digit A roads.
🛣️ A1 - London to Edinburgh (east side)
🛣️ A2 - London to Dover
🛣️ A3 - London to Portsmouth
🛣️ A4 - London to Bristol
🛣️ A5 - London to Holyhead
🛣️ A6 - Luton to Carlisle
🛣️ A7 - Carlisle to Edinburgh
🛣️ A8 - Edinburgh to Greenock
🛣️ A9 - Falkirk to Thurso
Once you know that, the rest starts making sense…
➡️ The A23 sits in Zone 2, between the A2 and A3, because it travels from London down towards Brighton.
➡️ The A27 also belongs in Zone 2, running east-west along the south coast, still between the A2 and A3 boundaries.
➡️ The A24, A22, and A21 all follow exactly the same logic.
Even many three and four-digit A roads follow this pattern too.
For example:
• A259 starts with a “2” because it’s in Zone 2.
• A270 (through Brighton) also begins with “2”.
• A272 crosses much of Sussex and Hampshire, but it still lives almost entirely within Zone 2.
It’s one of those little bits of road trivia that you’ll never notice… until someone points it out. Then you can’t unsee it! 👀
