People visiting adultwebsites will soon have to prove they are 18, according to Government plans.
The change will come into effect on July 15 and require visitors to adult websites from British IP addresses to provide their proof of age before being granted access.
It is being implemented in a bid to stop children viewing harmful content on the internet amid fears that it is damaging their social development and mental health.
However, the new rules are limited in their scope as they only apply to websites where more than a third of the content is adult or which operate on a commercial basis by charging a fee or earning revenue through adverts.
People will also still be able to access adult websites by using a virtual private network (VPN) that conceals their origin.
The House of Commons passed legislation on the rules last year but implementation has been repeatedly delayed due to lack of consensus on the age verification process.
Acceptable ways of proving age include a PortesCard, a type of age verification voucher that can be bought from shops, or uploaded ID documents.
New age verification services will also allow people to register with their proof of ID and enable them to log into adult sites using a 'token' that is stored in their internet browser.
"The introduction of mandatory age-verification is a world-first, and we've taken the time to balance privacy concerns with the need to protect children from inappropriate content," said the Minister for Digital Margot James.
"We want the UK to be the safest place in the world to be online, and these new laws will help us achieve this."
