A new study has found that teenagers are more aware than ever of how to hide inappropriate online activity from their parents.
The survey found that teenagers used tactics such as minimising Internet browsers when a parent entered the room, clearing browser histories, and creating private email addresses without parents being aware were commonplace.
The study of 400 parents and teenagers found that 50 percent of parents expressed confidence they know how to track what their child does online.
It found that only a fifth of teens said they didn't know how to hide their behaviour from their parents, the Telegraph reports.
Almost one in three British parents made no effort at all to monitor their teenager's activity online, compared with less than one in five in other European countries.
The study found that nearly 30.5 percent of teenagers admitted visiting websites of which their parents would disapprove.
It found that 25 percent of teenagers intentionally searched for nude images or pornography online, with over half (54 percent) viewed these images up to a few times a month, which is the highest in Europe.
Nearly 19 percent of teenagers admitted to downloading pirated music online and 6 percent said they had purchased alcohol or drugs over the Internet.
The study found that only 12 percent of British parents had a conversation about Internet security with their teenagers, fostering uncertainty on the part of children who may be unaware of what constitutes appropriate online behaviour.
Just over one in five parents (21.5 percent) admitted that their teenager is more tech-savvy than they are and that they will never be able to keep up with their online behaviours.
"We believe the data will come as quite a shock to some parents, and we hope it will encourage them to take immediate action to protect their children," Raj Samani, EMEA CTO at McAfee, the internet security company which commissioned the study, said.
"It is clear that a huge gap exists between what teens are doing online, and what parents are aware of. Parents must take an active role to ensure their teens are practicing safe online behaviour," he added.