Our rule of thumb: if it mattered, they'll leave a message or call again. People who genuinely need you - a surgery, a school, a delivery driver - usually do one or the other. Scammers and dialler systems mostly don't, because they are calling thousands of numbers and only want the people who ring back.
The 60-second check
- Voicemail or text? A clear message with a name and reason is a good sign.
- What type of number is it? Look at the prefix before anything else.
- What do others say? Search the number on Who Rang for reports.
- Were you expecting a call? An appointment, a job application or a parcel makes an unknown call more likely to be genuine.
Prefixes that change the answer
| Number starts with | Call back? |
|---|---|
| 01, 02, 03, 07 (mobile) | Usually low cost; check reports first |
| 080 | Free to call; still check who it is |
| 070 | Looks like a mobile but isn't - check your provider's price first |
| 084, 087 | Extra service charge; ring only if you know the organisation |
| 09 | Premium rate - don't call back an unexpected one |
| + followed by a foreign code | Don't call back a missed call you weren't expecting |
The last row matters most. A missed call that rings once from abroad is a classic trick to get you to call a number that charges you. Our dialling codes page explains each type of number and what calling it costs.
If the caller claims to be a company
If a voicemail says it's your bank, HMRC, your energy supplier or a delivery firm, don't use the number from the voicemail or your call log. Find the official number yourself on your card, bill or the organisation's website. A genuine issue will still be there when you call.
The trade-off
Ignoring every unknown number costs something: missed appointments, a missed job offer or a courier who gives up. Calling back everything costs something too. The check above takes a minute and avoids both. If you already rang back a number and now think it was spam, see what happens if you ring back a spam number.