If you answered, said hello and then realised it was a spam call, you haven't done anything dangerous. We say this first because a lot of online advice makes a normal reflex sound like a security breach. Answering the phone is not the risky part. What happens after hello is.

What your hello actually does

Many spam calls are placed by automated diallers that ring huge lists of numbers and only connect a human agent, or a recording, when someone answers. When you say hello, the system learns two things: the number exists, and a real person picks up. Numbers that answer can end up called more often or passed on to other lists.

That is the whole mechanism. Your voice doesn't unlock your phone, your hello doesn't authorise a payment and no data is taken from your device by answering an ordinary call.

The "can you hear me?" worry

You may have read that scammers record you saying "yes" and use it to sign you up for things. The story has circulated for years, but consumer groups have found little evidence of people losing money this way. A voice clip on its own doesn't give anyone your card details or access to your accounts. Still, there's no reason to help: if a caller opens with "can you hear me?", you can simply hang up.

When a spam call does become risky

  • You confirm personal details such as your name, date of birth or address.
  • You press a number "to be removed" or "to speak to an adviser".
  • You read out a code sent to you by text.
  • You agree to install an app or visit a website.
  • You make a payment or give card details.

If none of these happened, you can relax. If one did, see what to do if you accidentally answered a spam call.

What to do now

  1. Hang up without engaging further. You don't owe the caller politeness.
  2. Look the number up on Who Rang and add a short report of what the call was.
  3. Block the number on your phone to stop that particular number.
  4. If you're on a mobile, text the word "call" to 7726 and follow the reply to report the number to your network.
  5. Register with the Telephone Preference Service if you haven't, to cut legitimate but unwanted sales calls.

Should you stop answering unknown numbers?

It depends on your life. Letting unknown numbers go to voicemail cuts spam, but it also sends the GP surgery, a courier or a job interview to voicemail. A middle way is to let unknown calls ring out and check the number before calling back. If you're curious about the silent version of this situation, read what happens if you answer a spam call but don't say anything.