Robert Verkaik: It's pistols at dawn in the Wild West world of the web

When cowboys and vigilantes take over the town it usually means that law and order has broken down.

In the Wild West world of the internet, cowboy law firms are now reported to be writing threatening letters to film and music file-sharers, while vigilante web groups have taken revenge by hacking into the lawyers' databases.

The cause of the disturbance is the increasingly bitter battle between illegal downloaders and those representing the entertainment and music industry, who want to protect their investments.

Playing the part of the sheriff is the Information Commissioner, Christopher Graham, who has been called in to deal with the possible breach of the data protection laws after it was claimed that ACS:Law may not have encrypted its data of internet users, some of whom say they are innocent of illegal file-sharing.

But Mr Graham's powers can only tackle the symptoms of what has become a growing problem of internet piracy. There is no doubt that illegal downloading in the UK has become a massive threat to the music and film industries – the question now is whether a law designed before the internet age was born is fit for purpose.

The penalties for copyright offences depend on their seriousness, but at the higher end of the scale they can lead to a £5,000 fine or six months' imprisonment. The worst cases may be sent to the Crown Court, which has the power to impose an unlimited fine and up to 10 years' imprisonment.

It is hardly surprising that those who only occasionally indulge in a spot of illegal downloading feel that the law is being used disproportionately. But it is worrying to discover that a growing number of law firms are taking advantage of the situation. What is required is a new law that makes the sentence fit the crime.