A call that hangs up can mean four quite different things, and the details of the call - how long it rang, whether you answered, the type of number - tell you which one you're dealing with.
The four usual explanations
| What happened | Most likely cause | Risk |
|---|---|---|
| You answered, heard silence, then the line cut | Dialler with no agent free (abandoned call) | Low - more calls likely |
| You answered, heard a click or beep, then nothing | System checking the number is live | Low |
| It rang once from a foreign number and stopped | One-ring (wangiri) scam | Only if you call back |
| A UK mobile rang briefly, once | Wrong number, lost signal or a pocket dial | Very low |
Abandoned and silent calls
Call centres use predictive diallers that ring several numbers for each available agent. When more people answer than there are agents, some calls are dropped or left silent. Ofcom treats silent and abandoned calls as persistent misuse and sets rules to limit them, including requiring an information message on abandoned calls. Operations that ignore the rules still produce them in large numbers.
One-ring calls
A call from abroad that rings once and hangs up is designed to make you curious. If you call back, you may reach a number that charges a high international rate, with part of the money going to the scammer. Receiving the call costs you nothing in the UK. Calling back does. See why you keep getting calls that only ring once for more on this.
What to do
- Don't call back a number you don't recognise, especially an international one.
- Look it up on Who Rang - hang-up calls from diallers usually have plenty of reports.
- Block numbers that repeat.
- If the same number keeps making silent calls, report it to Ofcom; if it's a company trying to sell something, report it to the ICO.
- On a BT landline, Call Protect (1572) can send withheld, international or known nuisance numbers to a junk voicemail.
When it's personal
If hang-up calls come at odd hours, from a withheld number, and feel targeted rather than random, keep a log of dates and times and speak to your phone provider. Persistent calls meant to cause distress can be a criminal offence, and the police can trace withheld numbers - see whether the police can trace no caller ID in the UK.