Primary school pupils in south Wales used a school computer to look at a porn site on the internet.

The education authority in Swansea is consulting information technology experts to try to ensure that there is no repeat of the incident.

It happened during a lesson at Mayals Primary School in Swansea, when one pupil accessed the site and others, aged 10 and 11, had a look before teachers could do anything.

Some parents complained to the council.

Richard Parry, Swansea County Council's director of education, confirmed that pupils had accessed "unauthorised" websites.

Preventative steps

"We are grateful to those who brought the situation to our attention so that remedial action can be taken," he said.

"The LEA has taken immediate preventative measures so that no child in a Swansea school will be able to access an unauthorised site.

"We want to reassure parents that we are working with our IT specialists and schools to ensure that there is no recurrence of the incident."

It was not immediately clear how the authority intended to fulfil this pledge.

Options

The problem is an ever-present one for schools using the internet, where material unsuitable for children is only ever a few clicks away.

There are various ways around this, such as using "firewalls" or filtering software to block undesirable sites.

The advice from the government agency which promotes information and communication technology, Becta, is that these are not foolproof.

Filtering products it tested on racist, pornographic or violent sites ranged in performance from excellent to poor.

It concludes:

• there are no foolproof filtering products
• they require regular administration and maintenance
• no filter can replace close supervision by staff

Filtering systems can also be run by the schools' internet service provider and are a requirement for the "managed services" providers Becta approves.

If the filtering operates by detecting particular words, the system might either not display the offending page or e-mail, or display it with the offending content obscured or removed.

Some can shut down the internet browser or lock the computer when a user tries to access banned content - and send an e-mail to alert the teacher.

Walled gardens are probably the safest option, offered by some internet service providers and local education authorities. These offer collections of pre-selected websites.

But search engines are usually not part of the package and another concern is that some apparently innocent site addresses can contain surprising content.