020 3523 0537
Also shown as:
- 020 3523 0537
- +44 20 3523 0537
AI Summary
Based on 6 community reports
This London number is generating a lot of suspicion, with many reports suggesting it's linked to unwanted sales calls. Callers claim to be from "Three" (3) Mobile, or a similar-sounding company, offering deals or asking people to switch networks. A worrying theme is them asking people to confirm their details, which could be a phishing tactic to steal personal information. Some reports mention the caller hanging up abruptly. Until there is further clarity, it is best to be cautious when answering calls from this number and avoid sharing any personal details.
6 verified reports
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
6 totalWould say it's a scam, but I wasn't here when the call came. Reading other reports, it's probably a scam.
Offering a discount of three on a new phone deal.
Said they were from 3 network. wanted me to switch to them but had to go through a spiel first.
Flagged as spam by Google or Android
Said they were three, asked me to confirm details to prove it, and then hung up.
Said they were from 3 Mobile (I think, the women speaking wasn't very clear and it kinda sounded like 3D Mobile) and that I had a contract with them, I said I don't think I do and they apologised and hung up.
Share Your Experience
Help others by reporting what happened
About 020 3523 0537
What type of number is 020 3523 0537?
The phone number 020 3523 0537 (also written as +44 20 3523 0537) 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 3523 0537 safe to answer?
Based on 6 community reports, this number has been frequently reported as spam or a potential scam. The current risk score is 85% with 3 reports marking it as spam .
Exercise extreme caution if you receive a call from this number. Do not share personal or financial information.
More on nuisance calls
Safety Score
Details
- Tel Number
- 020 3523 0537
- Country
- 🇬🇧 United Kingdom
- Network
- Colt Technology Services
- Area
- London
- Type
- Geographic
- First Seen
- 25 Mar 2026
Protection Guides
How to Block This Number
Step-by-step instructions for iPhone, Android, and landlines
HMRC Tax Scam Calls
How fraudsters pretend to be HMRC and threaten arrest over fake tax debts, or offer bogus refunds to steal your details. How to spot them and what to do.
Bank Impersonation Calls
How fraudsters pose as your bank's fraud team, spoof their number, and trick you into moving money. What to look out for and what to do.
Still Getting Calls Despite TPS?
Why you might still receive calls after registering with TPS, and what you can do about overseas scammers ignoring the register.
Location
London, United Kingdom
This number originates from the London area code region. The map shows the general geographic area, not an exact location.
Call Types
Breakdown of reported call reasons. Larger segments and bars represent a bigger share of reports.
Is this your number?
Claim ownership to manage reports
We'll verify ownership via callback or documentation