O2 mobileAndy Hepburn/PA Wire

O2 customers have been warned of the risks of discussing anything personal or financial on their O2 mobile phones, because a glitch means that some customers have overheard the conversations of others.

So what's going on, and what are the risks?


A glitch

The company has admitted that a glitch hit customers in the Birmingham area this week. According to the Daily Mail, dozens of mobile customers have reported being able to overhear the conversations of strangers on their phone. They can't be heard, but they can listen in on conversations.

Others reported being switched from the call they were on to a call with a stranger unexpectedly.

Customers turned to Twitter to discuss the issue, including several in the Midlands.@sophieeeee_k said: "is anyone else on o2 having crossed lines?! ive had two in a week lmfao what if i was having a dead private conversation" @captain_az said Hey ‪@o2‬ is there a reason I keep getting a crossed line? Twice now I've had my call dropped and listened in to another call."

An O2 spokesperson told the Mail: "We had a problem with a network card responsible for transferring call traffic in the Birmingham area which resulted in a handful of customers experiencing crossed lines during phone conversations. Our engineers identified that a cable linked to the card was not working correctly and fixed the problem at 6.15pm on Tuesday. We have been monitoring the situation closely with no further reported issues. We apologise for any inconvenience caused to our customers."

All over?

So is this a storm in a teacup? Not necessarily.

The Daily Telegraph said that the issue had first arisen on Monday. It started in the Birmingham area, but there were reports of it affecting callers in Scotland, Wales and Liverpool.

On Twitter, @Rally_boy2009 said: "O2 crossed lines only in Birm area?! I don't think so - had 3 calls on Monday in ‪@MiltonKeynes_MK‬ go haywire!"

Even assuming that this problem is completely sorted now, it's a reminder that we should always be circumspect about what we say on the phone. Phone calls are never 100% guaranteed to be private, so it's never a good idea to give details of passwords and PINs, or talk in detail about personal or financial things that we would rather not share with the rest of the world.

It's not just the danger of crossed lines, but of people listening in at either end, and even hacking the call itself.

As financial expert Martin Lewis said on Twitter: "In summary of the o2 'crossed-wires' phone problem - don't be afraid to use your phone - but best to avoid banking and bonking conversations."