A new poll has found that one in six pupils have accessed pornographic websites on school computers.
Children aged 11 to 16 admitted to side-stepping teachers’ safeguards according to the study, commissioned by an internet service provider.
The revelation follows widespread concern about the number of young people sending sexually explicit messages by phone and social media.
The poll by Daisy Group interviewed 1,000 children of secondary school age.
It found that four in ten pupils view ‘unsuitable’ websites with inappropriate content such as violence.
Only a quarter of the pupils asked said that they had been blocked by internet security settings when they tried to access inappropriate websites.
Norman Wells, Director of the Family Education Trust, said that the findings would alarm parents.
He said: “Much more needs to be done to ensure that controls are watertight and school staff need to closely supervise pupils in classes where they have internet access.”
Chief Technology Officer at Daisy Group, Nathan Marke, cautioned: “We have a generation of children that are digital natives. They are incredibly IT-savvy and able to circumnavigate the simple controls that many schools have in place.”
The results of the survey come after teachers were given new powers to delete sexually explicit images found on pupils’ phones.
Former Culture Secretary Maria Miller told the MailOnline that children must be taught that sharing explicit images is a crime.
Earlier this month a child protection expert warned that celebrities are the cause of a sharp rise in the number of children sending sexually explicit text messages.
Speaking to the Commons Education Committee, Dr Zoe Hilton said that children may be unaware of the dangerous repercussions of sharing explicit pictures.
She commented: “I think we’ve got to the point with older teenagers where sexting is actually a normative behaviour”.