Medium risk
020 3455 1621
AI Summary
Based on 5 community reports
This London number, carried by Telecom2, has generated mixed reports with no strong community consensus yet. Some callers claim to be energy advisors or conducting home insulation surveys, asking personal questions like your age before abruptly hanging up when questioned—a potential sign of data harvesting. Other reports describe silent calls or hang-ups with nobody responding when you answer, which suggests either an automated dialler or intentional nuisance calling. The pattern of calls stopping after a few attempts is typical of numbers testing which accounts are active. While not definitively a scam, the combination of suspicious questioning and silent calls warrants caution. Don't share personal information with unsolicited callers claiming to be energy advisors, and consider blocking the number if it continues to contact you.
Written automatically by AI from the community reports on this page. It does not set the spam score, and it can make mistakes, so read the reports below as well.
Pattern detected: Energy supplier scam
Several community reports about this number describe the same experience.
Multiple reports mention a caller claiming to be from an energy supplier. This reported pattern suggests the displayed number may be used in an energy supplier impersonation attempt.
Based on screened community reports only. Caller ID can be spoofed, so reports may describe misuse of the displayed number rather than the registered number owner.
Common details reported
Details that appear in two or more community reports about this number.
- Reported scam type
- Energy supplier scam
- Recommended action
- Contact your energy supplier directly using the number on a recent bill before acting on any claim.
5 moderated reports
Every report on this page was screened automatically and then approved by a moderator before being published and counted towards the score. How moderation works
Cumulative spam score based on all reports up to each month. Higher percentage means higher reported scam risk. Cumulative spam score based on all reports up to each week. Higher percentage means higher reported scam risk. Cumulative spam score based on all reports up to each day. Higher percentage means higher reported scam risk.
Most helpful reports
5 totalSubmitted by users and shown as written, so wording and spelling are their own. Each report is screened and approved by the CallerCheck Moderation Team before it appears.
Said they were doing an energy survey about lodt insulation. They asked me some questions but then wanted to know my age, when I asked what does my age have to do with the questions they hung up.
A silent phone call at 15.03 on the 26th of March.
When you say hello, nobody answers.
This number rang twice over 2 days, then went quiet.
Said they were my local energy advisor
Share Your Experience
Help others by reporting what happened
How this page was checked
This profile is built from community reports, lookup activity and CallerCheck risk signals. It is not written by hand for this number, so the details below show who checks what and when it last changed. The risk score is based on community reports about calls and texts from this displayed number. It is not based on official records of who owns the number.
- Reports moderated by
- CallerCheck Moderation Team
- Safety guidance reviewed by
- CallerCheck Editorial Team
- AI summary
- Generated from approved community reports only
- Last report received
- 06 Mar 2026
- Last reviewed
- Reviewed automatically from current approved report data
- AI summary last generated
- 02 Sep 2026
- Last materially updated
- 02 Sep 2026
What do these dates mean?
Report and lookup dates come from user activity. Review dates show when CallerCheck last checked reports, safety guidance, or risk signals. We use “last materially updated” only for meaningful page changes, not cosmetic changes.
- First seen:
- when this number first appeared on CallerCheck, through its first lookup or report.
- Last report received:
- the most recent approved community report for this number.
- Last lookup:
- the most recent time a user searched for this number.
- AI summary last generated:
- when the AI summary on this page was last rewritten from the approved community reports.
- Last reviewed:
- the most recent human moderation or editorial review, where available.
- Last materially updated:
- the most recent meaningful change to this page: a new approved report, a risk score change, an AI summary regeneration, a moderation action, or a claim or dispute change. It does not move for cosmetic changes.
Sources and safety guidance
- Community reports about this number, screened before they are published or counted. How moderation works
- Ofcom numbering allocation data for the network this range belongs to
- Safety guidance aligned with UK scam-reporting advice, such as Action Fraud guidance, forwarding spam texts to 7726, and the 159 banking helpline where relevant. Where to report a nuisance call
Important limits
Caller ID can be spoofed, so a high risk rating means people have reported suspicious activity involving this displayed number. It does not prove that the registered owner of the number made the call or text. Community reports describe individual experiences and are not official confirmation of a scam. How caller ID spoofing works.
Own or manage this number? If this number belongs to you or your organisation, you can claim or dispute this profile. We review claims, check supporting information, and may update the page if reports appear to involve spoofing, mistaken identity, or outdated information. Claim or dispute this number
About 020 3455 1621
What type of number is 020 3455 1621?
The phone number 020 3455 1621 (also written as +44 20 3455 1621) is a UK landline number originating from the London area in Greater London . Calls to this number are charged at standard UK landline rates, usually included in call packages.
Is 020 3455 1621 safe to answer?
Based on 5 community reports, this number has received mixed reports from our community. The current risk score is 52% .
Be cautious when answering calls from this number. Verify the caller's identity before sharing any information.
What this data can and cannot tell you
Everything on this page comes from reports submitted by members of the public about calls and texts that showed this number. Caller ID can be spoofed, so the person contacting you may not be the genuine holder of the number, and a legitimate number can be misused. Before paying anything or acting on a message, check the claim with the organisation involved using contact details from its official website or letters, never the ones in the message itself.
More on nuisance calls
Safety score
5 reportsHow this score was worked out
Each report rates the number as safe, unknown, suspicious or spam. The score blends those ratings, giving more weight to the more serious ones, and a number with only a few reports is held closer to neutral until more arrive. Feedback votes on reports can also influence it slightly. Scores of 70% and above count as high risk, 40% to 69% as medium, and below 40% as low. More about spam scores
Why this number is rated Medium Risk
This number is rated Medium Risk because community reports are mixed: 2 of 5 describe spam or suspicious activity, while 3 describe a legitimate or unknown call, and several reports describe the same energy supplier scam.
Ratings reflect screened community reports, not official records. How the spam score works.
Confidence: Medium
Based on 5 community reports with repeated matching details. Confidence describes how much report evidence sits behind this page, and is separate from the spam score.
Caller ID can be spoofed, so reports may describe misuse of the displayed number rather than the registered number owner.
Details
- Tel Number
- 020 3455 1621
- Country
- 🇬🇧 United Kingdom
- Network
- Telecom2
- Area
- London
- Type
- Geographic
- Coverage
- London and the surrounding area
- Cost to call
- Standard landline rate
- First Seen
- 18 Feb 2026
Network shows the operator this number range is allocated to in Ofcom numbering data, so the caller may be on a different network if the number was moved or spoofed. First Seen is the date this number first appeared on CallerCheck.
What To Do Now
Steps that fit the energy supplier scam pattern reporters describe.
-
1
Do not share personal or payment details
Do not give personal information, card details or security codes to an unexpected caller or message.
-
2
Verify independently
If the caller claimed to be an organisation, find its official contact details yourself and check the claim directly.
-
3
Block and report the number
Stop further contact from 020 3455 1621 and forward scam texts to 7726. How to block a number on any phone.
Already paid or shared bank details? Call your bank straight away using the number on the back of your card, or dial 159 to be connected to your bank securely.
Call Types
Breakdown of reported call reasons. Larger segments and bars represent a bigger share of reports.
Location
London, United Kingdom
This number originates from the London area code region. The map shows the general geographic area, not an exact location.
Protection Guides
How to Block This Number
Clear instructions for iPhone, Android, and landlines
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We review claims carefully and may keep warnings visible where community reports still indicate risk.