The “Missed Call” scam is very basic and extremely effective, dependant on no more than a return call from those mobile phone users trusting enough to believe that someone is trying to contact them for genuine reasons.

So how does it work? – A computer is set up to pick numbers from a list and calls them automatically. After one ring the computer hangs up and the targeted handset indicates that a call has been missed. At this point completion of the scam relies on the owner of the mobile phone returning the call shown as missed on his/her handset.

Curiosity is the key factor on which the success of this scam has been based, and the scammers know that a large percentage of phone users will almost always return a missed call simply to find out the origin and purpose of it.

On returning the call, the owner of the targeted mobile phone is redirected to a premium rate telephone service and increasingly without his/her knowledge. The scammers then take this opportunity and ensure that the maximum amount of money is made from the call by entering into a lengthy conversation, generally relating to some bogus prize or competition.

Often, it is not until the monthly statement arrives that the targeted individual realises that his/her phone has been subjected to a “Missed Call” scam and charged excessive rates for the privilege.

At present there appears to be no immediate action which those exposed to this scam can take to ensure that others do not suffer the same fate.

The best way to prevent this scam is to apply caution, and only return missed calls to those numbers you recognise. And remember, if someone is genuinely trying to get hold of you, they'll call again.

More details on the numbers you need to watch out for and where you might get help if this scam happens to you are available on: www.digital-phone.co.uk/mobile-phone-scams/missed-calls.asp