As games firms are getting tougher on illegal file sharers, and cracking down on pirates, it appears they could also be accusing hundreds of innocent people in the process.

These claims come from a Which? Computing investigation, which was kicked off when the magazine was contacted by Gill and Ken Murdoch from Scotland, who were accused of sharing Atari's Race07.

The snag in all of this is that the couple told Which they've never played a computer game in their lives.

Although the case has now been dropped, the magazine believes that there are many more people like the Murdochs who have been falsely accused.

Law firm Davenport Lyons has been hired by a number of games firms, including Atari, to prosecute file-sharers, and the company has been monitoring peer-to-peer sharing networks such as BitTorrent and eDonkey to find them.

The lawyers in the Atari case that wrongly snagged Mr and Mrs Murdoch had turned to anti-piracy firm Logistep, which finds people illegally sharing files via their IP address.

Once they have the IP, rights owners can apply for a court order which means ISPs have to hand over the details for the account holder.

This is what happened to the Murdochs, and they received a £500 compensation letter or the threat of a court case.

Gill Murdoch, 54, and her husband, 66, said: "We do not have, and have never had, any computer game or sharing software. We did not even know what peer to peer was until we received the letter."

Intellectual property solicitor with law firm Lawdit, Michael Coyle is currently pursuing 70 cases of people who have been wrongly accused of piracy and spoken to "hundreds" of others.

"Some of them are senior citizens who don't know what a game is, let alone the software that allows them to be shared", he said.

It seems the most common problems are caused when pirates "piggyback" on an unsecured wireless network.

Many prosecutors are arguing that users are legally required to secure their network, but Mr Coyle points out that there is no section of the Copyrigtht Act that makes this a legal requirement. He does, however, admit it is the sensible thing to do.

Strangely, Mr and Mrs Murdoch do not have a wireless network so it is still unknown how their IP address became linked to file-sharing. It certainly seems that IP addresses are not enough to go on to accuse people of piracy, and Mr Coyle agrees.

"The IP address alone doesn't tell you anything. Piracy is only established beyond doubt if the hard-drive is examined", he said.

In fact, file-sharing site Pirate Bay admits it inserts random IP addresses into the list of people downloading files in an attempt to throw lawyers off track.

Still despite such problems, we have seen rights owners successfully sue pirates in recent months.

Topware Interactive won a landmark case in August, awarded more than £16,000 in damages after Isabella Barwinska from London shared a copy of the game Dream Pinball 3D.