Why do British numbers start with 07?

Why Do UK Mobile Numbers Start with 07?

If you've ever looked at a British phone number and wondered why so many mobiles start with 07, you're not alone. The answer lies in how the UK's numbering system is structured. Since the late 1990s, numbers beginning with 07 have been primarily reserved for mobile phones, making it easy to identify a mobile number at a glance.

When mobile networks began expanding in the UK, regulators needed a way to clearly separate mobile lines from landlines. The 07 prefix became the standard, helping both networks and users distinguish mobile traffic. Today, nearly all UK mobile numbers — whether on pay-as-you-go or contract plans — start with 07, followed by nine additional digits.

However, not all 07 numbers are the same. There’s an important exception: 070 numbers. While they technically fall under the 07 range, they are not mobile numbers. Instead, 070s are personal numbering services, often used to forward calls to another phone — sometimes internationally. Because of this, calling an 070 number can be surprisingly expensive, often costing as much as calling a premium rate line.

This has led to confusion — and even scams — where people assume an 070 number is a standard mobile. Ofcom, the UK’s communications regulator, has worked to crack down on misuse, but it’s still wise to be cautious.

So, while 07 has become synonymous with UK mobiles, it pays to know the difference. A true mobile number will usually start with 071, 072, 073, 074, 075, 077, or 078 — not 070. Understanding this small detail can save you time, money, and a few headaches.