SO WHY IS INTERNET PORNOGRAPHY SO HARD TO POLICE?

Q How prevalent is child pornography on the internet?

A It is estimated that more than 27,000 people access child pornography sites every day. The number of sites is anyone's guess, but the number of pictures runs into millions. One recent study suggested that half of all non-academic searches on the internet are for pornography. Child pornography is a tiny, but worrying, fraction of that.

Q Why can't internet companies refuse child porn sites?

A Often the "sites" are one person's computer, connected to the internet from home via an internet provider who cannot know what is there. The sheer number of home pages being created and changed every day makes it impossible for providers to know precisely what is there.

Q Why can't the law deal more effectively with pornography on the internet?

A If you get a magazine with pictures that are legal in Holland but obscene in Britain to Dover, the police can arrest you. If you access the magazine's website in Holland from Dover, the police may never know, nor can they get the website closed.

Q What counts as child pornography in Britain?

A Under the Child Protection Act 1978, amended in the 1994 Criminal Justice Act to cover images scanned into computers or downloaded from the internet, it is illegal to possess indecent photographs of children under 16. "Indecent" is defined as conduct the average person would find shocking or revolting. Each case is a question of fact left to the jury. "Possession" includes having the image in a computer-readable format - such as on your hard disk.

Q Are all pornographic images of children on the net "real"?

A No, some are "pseudo-photographs" created by electronic montages (a child's face on an adult body). This is illegal in Britain and the US.

Q Is anyone trying to stop this material being on the net?

A Yes, but Scotland Yard's paedophilia unit has only two staff. Most help comes from cyber-vigilantes. The US-based "Cyberangels" has an international division, with nearly 40 members in the UK who report suspicious sites. There's also Ethical Hackers Against Paedophilia, and the Internet Watch Foundation, which was set up by the Home Office, DTI, police and internet providers. It runs a hotline for anyone to report potentially illegal material.

Q Do people report?

A Since the UK's Internet Watch Foundation started, 2,200 sites have been reported to it. Almost all originate from outside the UK, though, so prosecutions have been rare.

Q What else is being done?

A A team at University College, Cork, is building the world's first database of child pornography to help police in Europe identify victims and perpetrators.

Q How can I stop my children straying near these sites?

A commercial "censorware" program (SurfWatch, NetNanny, CyberPatrol) will block access. They allow you to monitor what your children watch. But all have flaws: NetNanny uses a keyword system, so searches for "Essex", "Takeshita" and "Scunthorpe" would fail. Cyber Patrol maintains a blacklist - but it is very American in its dislikes (especially in religion), and new porn sites pop up every day.

Q What works the best?

A Be a parent. Talk to your child about what is out there, and answer questions truthfully. Personal details should not be put online. Keep the computer in a shared room. Above all, remember that you are trying to nurture an adult - not preserve a child.

EMMA COOK, CHARLES ARTHUR, JANE HUGHES