HORRIFIED parents today spoke of their dismay after primary school children were allowed to download pornographic images while in the classroom.

And they blasted school chiefs for not having the correct measures in place to prevent the youngsters from accessing prohibited sites.

The school involved today blamed a problem with the internet "firewall" installed by the county council, which prevents children from accessing sites of a sexual or obscene nature.

Education bosses said a new system was being put in at the school tomorrow to prevent any similar incidents - and said the problems were an "isolated incident."

Angry parent John Thompson, 37, of Lawrence Avenue, Burnley, said he was shocked when his 10-year-old daughter Kerriann asked him questions of a sexual nature.

He said Kerriann, who attends Cherry Fold Community Primary School, Cog Lane, Burnley, saw the image on a website while in class during playtime on Friday.

Mr Thompson, a former worker at Burnley's Papermarc, said: "I couldn't believe what I was hearing.

"She said she'd seen it at school on a computer and described a picture to me which I was horrified at.

"How do you explain that kind of thing to a 10-year-old child?"

A member of staff at the school, who asked not to be named, said: "I don't know how they managed to gain access to the sites but they did and were all laughing.

"It's ridiculous that they were able to gain access to something like this."

Peter Booth, second headteacher at Cherry Fold Primary School, said: "The school is aware that there was a problem with the county's firewall.

"We've stopped children from accessing the internet until the situation is resolved.

"We apologise for any distress caused and we will try our utmost to prevent such a situation from happening again."

A spokeman for Lancashire County Council, the education authority, added: "The system the school uses is a 'walled garden' system which is considered to be extremely safe.

"But the internet is growing rapidly on a day-to-day basis and, unfortunately, new unsuitable websites can appear which cannot be blocked immediately.

"This particular school is having a new system installed tomorrow which should allow teachers to monitor web access more easily and promptly block unsuitable sites. However, we do consider the internet to be an extremely useful educational tool and stress that this is an isolated incident."