How to Report Nuisance Callers to Ofcom

The Challenge of Reporting Hidden Callers

Reporting severe harassment, persistent telemarketing, or scam calls to UK authorities like Ofcom or the Information Commissioner's Office (ICO) is critical for stopping illegal activity. However, there is a major roadblock: you cannot effectively report a "No Caller ID" call because there is no actionable data to investigate.

Step 1: Gather the Evidence (Unmasking)

Before making a report, you need the perpetrator's actual phone number. By using a call intelligence tool like MaskOff UK, you can intercept the hidden call and strip away the anonymity block.

• Decline the anonymous call to route it to our secure system.
• Instantly receive the real UK or international phone number.
• Log the exact date, time, and duration of the call (available in your dashboard).

Step 2: Where to File Your Report

Depending on the nature of the call, you should report the unmasked number to the appropriate UK authority:

• Ofcom / ICO: Best for silent calls, abandoned calls, and unsolicited marketing/sales calls (especially if you are registered with the Telephone Preference Service - TPS).
• Action Fraud: If the caller was attempting a scam, phishing for financial data, or trying to defraud you, report it directly to Action Fraud (the UK's national reporting centre for fraud and cybercrime).
• Local UK Police (101): If the calls constitute severe harassment, threats of violence, or stalking, contact the police using the non-emergency 101 number, providing the unmasked number as evidence.

Taking Back Control

By unmasking hidden numbers, you stop being a passive victim and gain the tools necessary to block them locally and hold them legally accountable.

Related UK Safety & Evidence Guides: Read our step-by-step guide on preparing 101 police-ready phone harassment evidence, review the 2026 UK study on chronic phone harassment, or learn how conditional call forwarding unmasks 141 calls.