A computer hacker managed to break through school firewalls to send an email containing hardcore pornography to students.

Pupils at Valley Park School in Huntsman Lane, Maidstone, were given the abrupt order to shut down their laptops and school computers during lessons when the discovery was made.

Staff immediately prevented access to all IT equipment after learning of the security breach in order to protect pupils from the indecent image.

The school immediately informed parents after staff were alerted to the obscene material at just after 1pm last Friday.

Lessons carried on despite there being no access to computers for its 1,200 pupils.

"Our email system was hacked into by an external party and a highly inappropriate email distributed to student mailboxes..." - head teacher Vic Ashdown

Once it was established the offensive material was contained to email only, the systems were switched back on with access to correspondence restricted.

Head teacher Vic Ashdown said: "Our email system was hacked into by an external party and a highly inappropriate email distributed to student mailboxes.

"This was spotted immediately by colleagues and at 13.08 the student email system was disabled ensuring students could not view the email.

"The offending email was then removed completely from all student accounts.

"Parents were informed immediately of the problem.

"We have re-set our firewalls to avoid any further breaches."

He added: "I would like to place on record my thanks to colleagues for their vigilance in reporting this issue so quickly."

A parent, who asked not to be named, said: "Pupils were told to turn off their laptops when the teacher came into the class because someone had loaded a hardcore porn virus onto all the pupils' laptops and school computers and it was going to take some time for the school and police to put the matter right.

"Pupils were unable to do their homework or lessons involving their laptops."

It is not known how many children, if any, viewed the vulgar image.

Police said they would not be taking any action.