A watchdog is calling on internet users to raise the alarm if they accidentally stumble on child sex abuse images.
The Internet Watch Foundation (IWF) said illegal online material can be reported to its experts anonymously.
A poll of young men conducted for the organisation found that 44% of respondents would contact police if they inadvertently found images of child sex abuse online.
Susie Hargreaves, chief executive of the IWF, said: "It's incredibly positive that over 40% of young men say that they would report it, if they accidentally stumbled on child sexual abuse imagery online.
"But we need to get that message out to more young people - and let them know that they can report these disturbing illegal images to our Hotline, anonymously."
The survey of 1,035 UK males aged 16-24 found that more than half (54%) identified child sex abuse images online as one of the biggest issues on the internet, while the same percentage flagged up online grooming.
Nearly half of those polled thought sexting had increased in the last year, while a third (35%) have observed a rise in revenge porn.
Since its launch almost 21 years ago, the IWF has identified and removed more than a quarter of a million web pages showing children being sexually abused.
The foundation has teamed up with Everton Football Club to launch a campaign aimed at raising awareness of internet safety.
Adam Green, head of safeguarding at Everton FC, said: "This is a unique safeguarding initiative and we're proud to be the first club to partner with the IWF.
"At Everton, we have a history of putting safeguarding first, both for our young players and in the wider Everton community.
"This project takes that message one step further - we want to help young men develop appropriate relationship behaviours, both online and offline.
"And, in a complex online world, we want to help keep our young players, staff and community participants safe."
Figures suggest police forces in England and Wales are recording an average of 15 child sex offences involving the internet every day.
Last month a police chief called on web giants to channel some of their "eye-watering" profits into efforts to stamp out child abuse content.
Durham chief constable Mike Barton challenged firms to do more to stop the material appearing in the first place.