Every UK mobile number begins 07, followed by three more digits that complete the five-digit prefix. That prefix identifies the network that originally issued the number. It does not tell you which network the number is on today.
Because every UK mobile number starts 07, the only digits available to build a pattern inside the prefix are the third, fourth and fifth. To get four identical digits in a row, the 7 has to be followed by three more sevens — which happens in exactly one prefix.
07777 is the only UK mobile prefix with four consecutive identical digits. Every other repeating prefix manages three: 07888, 07999, 07555 and 07444 each carry three identical digits, not four.
That single extra digit shows up directly in price. Across our own stock, 07777 numbers start from £50 (as of September 2026), with the most distinctive examples priced considerably higher. No other repeating-digit prefix in our current stock commands the same premium. For a full breakdown of 07777 pricing and patterns, see our 07777 numbers guide.
The digit helps too: 777 is the classic slot-machine jackpot, and seven is treated as auspicious in both Western and Islamic tradition.
Browse the 07777 numbers in stock.
| Prefix | Originally issued by |
|---|---|
| Standard prefixes (no repeating digits) | |
| 07400 | Three |
| 07500 | Vodafone |
| 07900 | Vodafone |
| Repeating-digit prefixes | |
| 07444 | Vodafone |
| 07555 | Vodafone |
| 07777 | EE |
| 07888 | Three |
| 07999 | O2 |
Only 07777 carries four identical digits in a row. 07444, 07555, 07888 and 07999 each carry three. For more on how repeating patterns affect price and rarity, see our guide to repeating digit mobile numbers.
Ofcom reserves 07700 900000 to 07700 900999 for use in television, film and radio drama, so that a script can put a mobile number on screen without it ringing a real person. Numbers in that block are never issued to customers and cannot be bought from any dealer.
If you have ever noticed that mobile numbers in British TV shows tend to start 07700 900, that is why.
It does not tell you the current network. Since UK number portability was introduced, any number can be moved to any network using a PAC code. A number issued as an EE 07777 may well be sitting on O2 today. The prefix records who issued it, nothing more.
It does not always mean a single operator. Ofcom allocates mobile numbers in blocks of 1,000 or 10,000, not in whole prefixes. Most five-digit prefixes do sit with one provider, but a minority are split between several — so a prefix-to-network table is a guide, not a guarantee for every individual number.
It matters, but less than the last six digits. An ordinary ending on any prefix is worth roughly the same. The prefix becomes decisive only when it forms part of the pattern — for example when the three eights of 07888 extend a number already built around eights, or when a 07777 number ends in sevens as well.
If the prefix is part of the pattern you want, choose the prefix first. In every other case, choose the number whose last six digits appeal to you most and treat the prefix as secondary — you can port it to whichever network you like either way.
Browse the 07777, 07888 and 07999 ranges, or the full collection.