Unwanted calls — spam, scams, silent calls and persistent marketing — are the single biggest complaint UK phone users raise with Ofcom. This guide collects every practical blocking and reporting route in one place: blocking a single number on your handset, turning on free network-level protection, cutting nuisance-call volume for good, and reporting scams to the right authority.
Block a number on your phone
iPhone
- Open Phone → Recents, tap the (i) icon next to the number, scroll down and tap Block this Caller.
- To stop all unknown numbers ringing you: Settings → Apps → Phone → Silence Unknown Callers. Calls from numbers not in your contacts go straight to voicemail and appear in Recents.
- You can review or unblock numbers under Settings → Apps → Phone → Blocked Contacts.
Android
- Open the Phone app, press and hold the number in your recent calls, then tap Block / Report spam.
- To filter suspected spam automatically: Phone → Settings → Caller ID & spam and turn on Filter spam calls. Google’s spam database screens callers before your phone rings.
- Manufacturer dialers (Samsung, Xiaomi, etc.) have an equivalent under Call settings → Block numbers.
Landline handsets
- Most modern DECT handsets (BT, Panasonic, Gigaset) have a built-in call-block list and a “block withheld numbers” option — check the handset’s Call Block menu.
- BT landline customers can enable BT Call Protect free of charge; TalkTalk offers CallSafe; Sky offers Sky Talk Shield. All three screen or divert known nuisance callers at the exchange, before your phone rings.
Turn on your network’s free spam protection
- EE — Scam Guard / call protect settings in the EE app.
- O2 — free spam-call identification and blocking in the O2 app.
- Vodafone — Secure Net includes scam-call flagging.
- Three — automatic scam-call filtering (calls flagged “Suspected spam”).
- Sky Mobile, giffgaff, Tesco Mobile and most MVNOs inherit the host network’s screening; check the account app for a “spam” or “call protection” toggle.
These services are free and work at network level, so they protect landline-style VoIP apps and older handsets too.
Cut nuisance-call volume for good
- Register with the Telephone Preference Service (TPS) at tpsonline.org.uk (free). UK companies are legally required to stop unsolicited sales calls to TPS-registered numbers within 28 days. Businesses can use the Corporate TPS.
- 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 rings.
- Never engage to “opt out”. Pressing a key to be removed, or speaking to “remove your number from our list”, only confirms your number is live — it usually means more calls.
- Don’t call unknown numbers back blind. Premium-rate (09), personal-number (070) and some service numbers can charge several pounds a minute. Look the number up first with our free UK number checker.
Report a scam or nuisance call
- Scam texts: forward the message free to 7726 (it spells “SPAM” on the keypad). Your network investigates and can block the sender for everyone.
- Scam or fraud calls: report to Action Fraud on 0300 123 2040 or actionfraud.police.uk (England, Wales & NI), or Police Scotland on 101. If you have transferred money, call your bank immediately using the number on the back of your card, then dial 159 — the anti-fraud hotline that connects you securely to your bank.
- Nuisance / marketing calls: report to the ICO at ico.org.uk — they fine repeat offenders — and to your network.
- Silent or abandoned calls: report to Ofcom at ofcom.org.uk/complaints.
What to do if you already answered
- Never share bank details, passwords, PINs or one-time security codes on a call you didn’t initiate — no bank, HMRC or delivery company will ever ask for them.
- If a caller claims to be your bank, hang up and call back on the number printed on your card — ideally from a different phone, or after waiting a few minutes.
- Don’t act under pressure. Urgency (“your account will be closed today”) is the single most reliable scam signal.
- If you’re worried a specific number that called you is a scam, look it up here — you’ll see its type, the Ofcom range holder, risk assessment and any community reports.
This guide is referenced from every number-lookup page on this site so the specific advice for each number stays short and the full instructions live in one always-up-to-date place.