You can stop nuisance calls and block unwanted numbers directly from your phone settings, through your network provider, or with a call-blocking app. Nuisance calls include cold sales calls, scam calls posing as your bank, and silent calls from automated dialers. UK mobile users receive 3 to 5 nuisance calls (or more) a week on average, and the numbers change constantly as scammers rotate through fresh lines. This guide covers every method to block a number on iPhone and Android, stop nuisance calls at network level, and report persistent callers to Ofcom in 2026.
How to Block a Number on iPhone
To block a number on your iPhone, open the Phone app, go to Recents, tap the "i" icon next to the number, scroll down, and tap Block this Caller. Confirm by tapping Block Contact in the pop-up.
Manage every blocked number from Settings > Phone > Blocked Contacts, where you can add or remove numbers at any time.
iOS also includes Silence Unknown Callers (Settings > Phone), which sends any number not saved in your contacts straight to voicemail. This stops nuisance calls before your phone even rings, though it also silences genuine callers such as delivery drivers or new clients, so switch it on only if unwanted calls have become frequent.
Recent iOS versions label suspected scam numbers as "Maybe: Spam" or flag them as likely nuisance calls directly on the incoming call screen, using carrier data rather than your own contact list. Treat any call flagged this way as unsafe to answer, and add it to your block list straight after it rings off.
If a blocked number keeps texting you instead of calling, blocking still applies. iOS blocks calls, FaceTime, and messages from the same number in one action, so you don't need to repeat the process for texts separately.
How to Block a Number on Android
To block a number on Android, open the Phone app, tap Recents, press and hold the number, then tap Block/report spam. The steps differ slightly by manufacturer.
Google Pixel and Stock Android
Open the Phone app, tap the three-dot menu next to the call in your Recents list, then select Block/report spam. Turn on Caller ID & Spam Protection under Phone app settings so Android flags likely spam numbers before you answer.
Samsung Galaxy
Open the Phone app, tap the three-dot menu in the top corner, choose Settings > Block numbers, then add the number manually or select it from your call log or messages.
Android's built-in spam database updates constantly, so numbers flagged as "Suspected Spam" get caught even before you add them to your own block list.
How to Block a Number From Cell Phone Messages
Open the Messages app, select the conversation, tap the contact name at the top, then choose Block, spam, and report. This blocks both future calls and texts from that number in one step on most Android handsets, matching the behaviour of the block feature on iPhone.
Blocking a Mobile Number Without Deleting the Contact
You don't need to delete a saved contact to block a mobile number. Both iPhone and Android keep blocked contacts in your address book, since the block list works independently and simply prevents those numbers from appearing in your call log or messages.
How to Stop Nuisance Calls on Mobile Without an App
You can stop nuisance calls on your mobile without installing anything, using free tools your network and the UK regulator already provide.
Register with the Telephone Preference Service (TPS). Sign up for free at tpsonline.org.uk. Registration takes up to 28 days (4 weeks) to reduce calls, as telemarketers must update their lists against the register.
Ask your network to activate free call barring. Every major UK network now offers this at no extra cost:
EE blocks the last number that called through 1572, and lets you bar international and premium-rate numbers in the My EE app.
O2 offers Call Block in the My O2 app, letting you block specific numbers directly from your call history.
Vodafone provides Call Barring in Settings under My Vodafone, covering international, premium, and withheld numbers.
Three lets you bar numbers through network settings or by contacting customer support directly.
Sky Mobile and giffgaff both support standard handset-level blocking, as neither operates a separate nuisance-call-barring system.
Turn on Caller Display so you can see a number before deciding whether to answer, if you would rather screen calls than block them outright.
Stopping Nuisance Calls on a Landline
If nuisance calls target your landline rather than your mobile, ask your provider about a call-blocking handset or a network-level barring feature. BT's Call Protect and TalkTalk's Call Safe both screen incoming numbers against a live list of reported scam callers and automatically divert flagged numbers, so the phone never rings for a known nuisance caller.
How to Recognise a Nuisance Call Before You Answer
A withheld number, a foreign dialling code you don't recognise, or repeated calls within minutes of each other are the 3 clearest signs of a nuisance call. Genuine businesses rarely call the same number twice in one hour, while automated dialers redial constantly until someone picks up.
Silent calls that connect but stay quiet for a few seconds come from automated dialing systems waiting to route you to a live agent, and count as nuisance calls under Ofcom rules even without a spoken word.
Spoofed local numbers mimic your own area code to increase the chance you'll answer, a tactic that has made caller ID far less reliable than it was 5 years ago.
Pre-recorded messages about accident claims, PPI, or a supposed problem with your bank account are illegal under UK telemarketing rules if you haven't given consent to be contacted.
If you're not sure whether a call was genuine, let it go to voicemail. Legitimate callers leave a message, while nuisance callers rarely do.
Blocking Nuisance Calls From Specific Number Ranges
Certain prefixes generate a disproportionate number of complaints, and understanding them helps you decide which calls to block on sight.
0151, 0121, and 0116 cover Liverpool, Birmingham, and Leicester. Scam call centres often route through these local landline prefixes to appear trustworthy, a tactic known as neighbour spoofing.
020 numbers that keep ringing you are frequently spoofed London numbers used by robocallers, not genuine local businesses, since real companies rarely cold-call the same person repeatedly within days.
073 mobile numbers often appear in nuisance call and spam text reports because this range is cheap to acquire in bulk for short-lived marketing campaigns.
07488 numbers have generated an increasing number of complaints about unsolicited texts and calls, and blocking the specific number remains the only reliable fix, since carriers cannot block an entire prefix for a single user.
Blocking works per number, not per prefix, unless you use a call-blocking app with pattern-based rules, so add each new number to your block list as it appears rather than waiting for a pattern to form.
Best Call-Blocking Apps in 2026
Call-blocking apps add value mainly by identifying unknown numbers before you answer, using databases built from millions of user reports.
Community-reported spam databases (used by apps such as Truecaller and Hiya) flag likely scam or sales numbers on the incoming call screen.
Reverse-lookup tools let you search for a number that has already called you, which is useful when a nuisance call goes to voicemail.
Visual voicemail apps permanently block persistent numbers and can tell repeat callers your number is no longer in service, which removes you from many telemarketing lists.
Check an app's privacy policy before installing it, since call-blocking apps require access to your contacts and call log to work effectively.
Most call-blocking apps work on a freemium model: free for basic number lookup and blocking, with a paid tier for unlimited reverse lookups and ad-free use. A free plan meets the needs of most UK mobile users who deal with a handful of nuisance numbers a week.
How to Avoid Nuisance Calls in the First Place
Prevention cuts nuisance calls faster than blocking numbers one at a time after they've already reached you.
Read the checkboxes before you tick them when signing up for a service online, since ticking the "share with trusted partners" box hands your number to unrelated marketing companies.
Give out your mobile number only when necessary, and use a secondary number or your email address for competitions, surveys, and free trials.
Go ex-directory with your network to remove your number from public phone listings, cutting off a common source telemarketers use to find new numbers.
Never reply "STOP" to a text from a number you don't recognise, since replying confirms your number is active and can increase the volume of nuisance texts you receive.
How to Report Nuisance Calls in the UK
To report a nuisance call, forward spam texts to 7726 (free on all UK networks), report scam or persistent nuisance calls directly to Ofcom, and complain to the Information Commissioner's Office (ICO) if a company keeps calling despite your TPS registration.
Unsolicited marketing calls that ignore the TPS register breach the Privacy and Electronic Communications Regulations (PECR), and Ofcom can fine offending companies up to £2 million, so your complaint carries real weight.
Before you complain, note the number, the time of the call, and what the caller said, since Ofcom and the ICO both ask for this detail to act on a report.
Choosing the Right Mobile Plan to Reduce Nuisance Calls
Some UK networks build stronger spam protection into their SIM plans than others, so it pays to check what's included before you switch. Compare UK SIM-only deals on SwitchSquid to see which networks bundle free call barring and spam identification as standard, and read our mobile network comparison guide if persistent nuisance calls are pushing you to switch provider altogether.
Frequently Asked Questions
Can I permanently block a number on my mobile?
Yes, you can permanently block a number on Android and iPhone through the built-in block list, and the block stays active until you remove it manually.
How do I bar a number from calling me?
To bar a number, add it to your phone's block list, or ask your network provider to bar it at network level, which also stops silent and international nuisance calls.
How long does TPS registration take to work?
TPS registration takes up to 28 days (4 weeks) to reduce nuisance calls, since telemarketing companies must update their call lists against the register on a monthly cycle.
Can I block a number that keeps changing (spoofed numbers)?
No, blocking a single number won't stop spoofed callers, since scammers rotate numbers constantly. Use your network's spam-detection feature or a call-blocking app instead if one number keeps reappearing under different digits.
Do UK mobile networks charge for call barring?
No, EE, O2, Vodafone, and Three all offer free call barring and nuisance call blocking as a standard account feature.
Is it illegal to make nuisance calls in the UK?
Yes, unsolicited marketing calls that ignore the TPS register breach PECR, and Ofcom can fine offending companies up to £2 million for repeated breaches.
How do I block a mobile number that keeps ringing me?
To block a mobile number, open your call log, select the number, and choose block, or add it manually through your phone's blocked contacts settings.
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