Beware of calling "missed call" numbers you don't recognise on your mobile phone is the advice being given as a new scam is discovered. Numbers beginning '0709 020' should be ignored.
Paul Whiteing from the mobile regulator is saying more needs to be done to prevent the scams. People ringing the numbers are being charged premium rates.
10,000 complaints about mobile spam were received by the Independent Committee for the Supervision of Standards of Telephone Information Services last year in the UK alone. Source