Mobile phone giant Vodafone is barring its customers from logging onto adult websites through their handsets in a bid to keep children away from porn.
The filters will help protect children from paedophiles
Vodafone users will need to prove they are over 18 before firewalls are lifted on pornographic websites or chat rooms dealing with adult themes.
It claims to be the first mobile phone operator in the world to launch a system to control internet access.
A filter will be used to identify websites of a pornographic nature.
Customers will be unable to access adult websites unless they specifically "opt in" and demand that the cyberspace blindfold is removed.
To remove the electronic filter, Vodafone customers will have to provide their credit card details either online, over the phone or by visiting a high street outlet.
Vodafone is banking on the fact that only adults have access to a credit card, although it admits this system of verification is not failsafe.
Al Russell, head of content services at Vodafone UK, accepted that children could use their parent's credit card to register.
"There has to be an element of parental supervision", he said. "They will also be able to spot on their credit card bill whether it has been used as part of the verification process."
There are around 47 million mobile phones in use in the UK, and more than 16 million of them have some form of internet access. This is expected to accelerate as more hi-tech "third generation" handsets scour the market.
Vodafone's decision to stop access to "unmoderated" chat rooms is designed to prevent paedophiles using handset technology to "groom" children for abuse.
Its new Content Control system came into force on 2 July and is born out of a code of practice agreed by the UK's six largest mobile phone operators in January.
With the explosion in new technology and now handheld internet access, child porn offences have rocketed by 1,500% since 1988, according to children's charity NCH.
John Carr, internet consultant for the charity, said: "What we would like now is for the mainstream internet industry to do the same thing."
Other mobile operators say they are currently working on similar content control barring devices.