Hackers taking control of home computers is becoming an increasing IT security problem, an expert asserts.

Graham Cluley, senior technology consultant at Sophos, commented that this issue is growing in the industry.

He said: "It is a prime way in which criminals these days commit crime and there're a variety of different things you can do once you have a botnet."

Mr Cluley explained that the most common use of such a program is sending spam, which can lead to cash benefits for hackers.

He added that 99 per cent of such messages are sent using botnets rather than a hacker's own computer, meaning that anyone could be unwillingly spreading adverts and messages as they are under the control of one of these applications.

A study by Sophos has revealed that the US hosts more malware on its websites and relays more spam through its computers than any other country.

According to a recent survey by Connect, the two biggest IT headaches for businesses were 'everyday hassles with IT' (37 per cent) and 'security concerns' (32 per cent).