Colt Spam Calls — UK Numbers Most Reported on Our Checker
Ranking of the Colt-allocated UK numbers most-looked-up on our free UK Phone Number Checker. These rankings reflect public lookup interest, which strongly correlates with scam / nuisance call reporting. Currently tracking 872 distinct numbers across 1,403 public lookups.
Advertisement
Top-looked-up Colt numbers
Click any number to see its full lookup page with risk-level, range holder, community reports and related numbers.
| Number | Searches | Last looked up |
|---|---|---|
| 020 3743 6966 | 27 | 11 Jun 2026 |
| 020 4514 7812 | 13 | 9 Jun 2026 |
| 020 4514 7466 | 11 | 10 Jun 2026 |
| 020 4514 8799 | 11 | 8 Jun 2026 |
| 020 3443 9837 | 9 | 21 May 2026 |
| 020 4514 9106 | 9 | 8 Jun 2026 |
| 020 4514 9121 | 9 | 8 Jun 2026 |
| 0161 564 7512 | 8 | 6 Jun 2026 |
| 020 3003 2417 | 8 | 6 Jun 2026 |
| 020 3523 0619 | 8 | 10 Jun 2026 |
| 020 4514 7814 | 8 | 6 Jun 2026 |
| 020 4514 8790 | 8 | 10 Jun 2026 |
| 0121 818 5128 | 7 | 10 Jun 2026 |
| 0161 564 5930 | 7 | 9 Jun 2026 |
| 020 4514 7425 | 7 | 9 Jun 2026 |
| 020 4514 8792 | 7 | 5 Jun 2026 |
| 0161 564 6625 | 6 | 12 Jun 2026 |
| 020 3433 1057 | 6 | 26 May 2026 |
| 020 3890 2207 | 6 | 11 Jun 2026 |
| 020 3932 2488 | 6 | 9 Jun 2026 |
About Colt in the Ofcom register
Colt is one of the UK communications providers allocated number ranges by Ofcom under the National Telephone Numbering Plan. Number allocations are recorded against the legal entity Colt Technology Services. Numbers within those ranges may now be in active use by the original allocated subscriber, may have been ported to another carrier under UK number portability rules, or may have been re-issued after being returned to the operator's pool — so the Ofcom range holder is not a guarantee of the current call source.
Colt's UK number allocation
Ofcom has allocated 2,005 number blocks to Colt Technology Services. Each block is typically 1,000 or 10,000 consecutive numbers. The mix below shows what kinds of numbers Colt runs — useful context for judging whether a call claiming to be from Colt is plausible.
| Number type | Allocated blocks | Share |
|---|---|---|
| Geographic landline (01 / 02) | 1,674 | 83% |
| UK-wide non-geographic (03) | 110 | 5% |
| Freephone & special-rate (08) | 98 | 5% |
| Premium rate (09) | 88 | 4% |
| Mobile (07) | 24 | 1% |
| Corporate & VoIP (056) | 7 | 0% |
| Service & access codes | 4 | 0% |
Are Colt numbers safe to answer?
Usually, yes — the vast majority of calls from Colt-allocated ranges are ordinary, legitimate calls. But a number sitting in a Colt range is not a guarantee of safety: fraudsters routinely spoof or hijack numbers from every major UK operator, and porting means a number may no longer be on Colt's network at all. Judge each call on what's actually said: never hand over bank details, passwords or one-time security codes to an unexpected caller, and if in doubt hang up and call the organisation back on a number you have verified independently.
How to block and report unwanted Colt calls
Block an unwanted number on your phone
- iPhone: open Phone → Recents, tap the (i) next to an unwanted number, scroll down and tap Block this Caller.
- Android: open the Phone app, press and hold an unwanted number in your recent calls, then tap Block / Report spam.
- Network level: EE, O2, Vodafone and Three all offer free spam-call blocking in their app or online account settings.
Report an unwanted number
- Scam texts: forward the message to 7726 (free) — it spells "SPAM" on the keypad — to report it to your mobile network.
- Scam or fraud calls: report to Action Fraud on 0300 123 2040 (England, Wales & NI) or Police Scotland on 101.
- Nuisance / marketing calls: report to the ICO and register with the free Telephone Preference Service (TPS) to reduce unsolicited sales calls.
How to stop unwanted calls for good
Blocking Colt numbers stops that one number, but determined nuisance callers simply switch numbers. These steps cut the volume across the board:
- Silence unknown callers. iPhone: Settings → Apps → Phone → Silence Unknown Callers. Android: open Phone → Settings → Caller ID & spam and turn on filtering. Unknown numbers go straight to voicemail.
- Turn on your network's free spam shield. EE, O2, Vodafone, Three, Sky and most providers offer free spam/scam-call screening in their app or account settings.
- Register with the Telephone Preference Service (TPS). It's free and legally obliges UK companies to stop unsolicited sales calls within 28 days.
- Use a dedicated call-blocker app if nuisance calls are persistent — these screen against live community spam databases and can auto-reject flagged callers before your phone even rings.
- Never engage to "opt out". Pressing a key to be removed only confirms your number is live and usually means more calls.
Frequently asked questions about Colt numbers
Are Colt numbers always genuine?
No. While Colt is allocated UK number ranges by Ofcom, scammers commonly spoof or hijack numbers from any UK operator's range. A number being in a Colt-allocated block does not guarantee the caller is Colt or Colt-owned.
How do I report a Colt spam call?
Forward spam SMS messages to 7726 (free of charge — works for all UK mobile networks). Report unsolicited marketing calls to the Information Commissioner's Office (ICO) at ico.org.uk/concerns. If you lost money to a scam call, report to Action Fraud at actionfraud.police.uk or 0300 123 2040.
How do I block a Colt number?
On iPhone, tap (i) next to the number in Recents and choose Block this Caller. On Android, long-press the number and choose Block / Report spam. To prevent unknown callers ringing through, enable Settings → Phone → Silence Unknown Callers (iPhone) or your dialler's spam filter (Android).
Why are some Colt numbers reported as scam more than others?
Fraudsters target ranges they know are widely allocated, so the volume of reports per Colt number reflects the size of the active block more than Colt's own conduct. Numbers in newer or larger ranges naturally see more reports purely on volume.
Check another UK number
Or use the free UK Phone Number Checker to look up any UK number — the result shows the Ofcom range holder, risk level, and any community reports on file. You can also add your own report directly on the checker results page.