Christian advocacy group CARE has welcomed the government's commitment to introducing age verification on porn sites.
It comes after years of pressure on the government over its decision to abandon age checks in 2019.
Digital Minister Chris Philp said today that all sites that publish porn will be forced to check the age of visitors in order to prevent underage access.
The age verification process will check that visitors own a credit card and are 18 or over.
Sites that fail to implement the checks are liable to receive substantial fines of up to a tenth of their annual worldwide turnover.
The announcement coincides with Safer Internet Day.
Mr Philp said: "It is too easy for children to access pornography online. Parents deserve peace of mind that their children are protected online from seeing things no child should see.
"We are now strengthening the Online Safety Bill so it applies to all porn sites to ensure we achieve our aim of making the internet a safer place for children."
CARE CEO Ross Hendry said the scheme was "long overdue".
"Today's announcement is hugely encouraging for all of us at CARE who have spent years calling for this safeguard," he said.
"Tens-of-thousands of children have stumbled across and continue to stumble across porn. They are disturbed, upset, and damaged by it. A just society does not allow this to happen, and it is good that the government has finally recognised our campaign.
"Some groups oppose this technology on the grounds that adults should not face any barrier to porn. They argue that barriers to access violate privacy or 'interfere with sexual freedom'.
"In a society that requires people to present proof of age to purchase alcohol, tobacco, or other adult products online, this is absurd. Adult convenience should never trump child safety."
