Fatty posted:

In the UK if you're called on a landline and hang up it doesn't actually terminate the call. The call is only terminated when the caller hangs up. This has lead to a scam where victims are called by the police/their bank, being told that illegal activity on their account has been detected, and they need to phone their banks fraud line now. The victim then hangs up and the scammer waits on the line. The victim makes a new call using the actual number they know is for their bank, the scammer hears a bunch of dial tones over the line, and then pretends to be a different person and gets the victim to give them account info. The scammer also frequently plays fake dial tones and ring tones to further fool the victim that their phone is working normally.

Its effective, because quite often the natural response for people who are very suspicious of scams is to hang up, and call the number thats been provided previously by their actual bank.