Your phone shows a number starting +1, perhaps with "United States" or "Texas" underneath. It might have rung at three in the morning, or left a garbled voicemail about your computer, your bank or a warrant. You have no family or business in America, so the obvious question is why it is calling you at all.
Why is a United States number calling me in the UK?
Almost always because someone is dialling enormous lists of numbers in the hope that a person picks up. Internet calling has made ringing the UK from anywhere in the world cheap, and a call can be set to display more or less any number the caller likes. The +1 on your screen tells you where the caller wants you to think they are. It proves nothing about where they actually sit.
It is also worth knowing that +1 is shared by the US, Canada and several Caribbean countries, so an "American" number is not always American. If the call was unexpected and you do not know anyone over there, assume it is not for your benefit until the caller shows otherwise.
Which US numbers are UK users looking up?
Several +1 numbers sit near the top of UnknownDial's searches. The descriptions below come from users' comments and are not proof of who actually placed the calls.
- +12102490540 shows as a Texas number. Users say a caller claiming to be from Microsoft told them their computer was downloading viruses and asked them to switch it on.
- +18006927753 has more than 40 comments, many describing calls from "Apple Support". One user points out that they do not own a single Apple product.
- +18004269400 is reported as spoofing a Microsoft help desk number, with callers saying someone had broken into the person's Microsoft or Outlook account.
- +18056377243 draws complaints about calls late at night and early in the morning, with no message left. One comment mentions a script about fraudulent activity linked to Social Security, a US government scheme that has nothing to do with people living in Britain.
What are 844, 855 and 888 numbers, and are they scams?
In the US, 800, 888, 877, 866, 855, 844 and 833 are toll-free codes, according to the Federal Communications Commission (fcc.gov). They do the same job as 0800 numbers here: free to call from inside the US, which is why large companies use them for customer helplines.
The code on its own is no sign of a scam, and plenty of genuine firms use 844 or 855 numbers. The problem is that a toll-free number looks official, which suits anyone pretending to be a tech support desk or a bank. From a UK phone, calling any +1 number back is an international call, and what you pay depends on your tariff.
Arrest warrant calls and other scripts to ignore
Many +1 calls carry scripts written for American targets. Voicemails saying there is a warrant out for your arrest, or that your Social Security number has been linked to fraud, are typical. None of it applies to someone living in the UK, and no police force settles a warrant with a payment taken over the phone.
Other scripts work anywhere. Tech support callers using the Microsoft or Apple name usually want remote access to your computer or a payment for a "fix". Automated bank calls may read out a verification code and ask you to confirm it. One UnknownDial user described a recorded call at 4am claiming to come from a Canadian bank; when they rang the bank directly, it said it had made no such call.
Why calls from abroad look different now
UK rules have changed how overseas calls appear on your phone. Since 29 January 2025, UK networks must block calls from abroad that display a UK landline number. Under Ofcom guidance from July 2026, calls from abroad showing a UK mobile number (+447) have their caller ID withheld unless the number can be verified.
The reason is simple. Ofcom found in July 2025 that around one in ten people answer calls from unknown international numbers, rising to about one in four when the number looks like a UK mobile. A familiar-looking number gets answered far more often, so taking that disguise away matters. A +1 number deserves the same caution: the display alone tells you very little about who is on the line.
I answered or called back. What should I do?
- If you called back and nothing else happened, check your next bill for international charges and contact your provider if anything looks wrong.
- If you let a caller onto your computer, disconnect it from the internet, remove any remote access program they asked you to install and run a security scan. Change your important passwords using a different device.
- If you gave card or bank details or paid anything, ring your bank at once. Dialling 159 connects you to the fraud teams of the main UK banks.
- Report any loss to Report Fraud at reportfraud.police.uk or on 0300 123 2040. In Scotland, contact Police Scotland on 101.
- If you spoke briefly and gave nothing away, block the number and carry on. More calls may follow for a while.
How to block US numbers and where to report them
On an iPhone, open Recents in the Phone app, tap the info icon beside the number and block it. Turning on Silence Unknown Callers in the Phone settings sends every number not in your contacts to voicemail, which suits anyone who rarely gets genuine calls from abroad. On Android, press and hold the number in your call log and choose Block or Block/report spam.
You can text the caller's number to 7726, free, so UK networks can look into it. Before deciding whether to answer or return any unfamiliar number, search it on UnknownDial and read what others have reported.
If you are reading this in the US, report scam calls to the Federal Trade Commission at reportfraud.ftc.gov, and add your number to the National Do Not Call Registry at donotcall.gov. The registry will not stop criminals, but it removes most legitimate telemarketing, which makes the remaining calls easier to spot.