Websites allowing children to access pornography will have payments blocked by banks Banks and credit companies will punish sites who do not co-operate with child protection measures They already monitor illegal porn websites but this is the first time they can punish sites who fail to keep explicit images away from under-age children This is the latest development of the opt-in system Cameron announced earlier this year which blocks porn from homes unless they ask for it Websites which allow children to access pornography will have payments made to them blocked by banks as part of a government crackdown it emerged last night. New proposals will see banks and credit card companies effectively police the internet by financially punishing sites that do not co-operate with safety measures. It is hoped the move will address the growing exposure of under-aged children to internet porn by starving purveyors of explicit images of paying customers, even if the material itself is not illegal. Incentive: The proposals are designed to encourage websites to comply with child safety measures by allowing banks to punish those who do not by blocking payments A "summit" between financial organisations and the video services regulator will be held next month in an effort to finalise the agreement, as reported in the Daily Telegraph. It is believed to be the first time banks have been asked to monitor the internet in such a way - by punishing those who do not act to prevent children from viewing their material. David Cameron has previously stated the exposure of highly explicit internet pornography to children is "corroding childhood" and made it a priority for Downing Street. Some websites do require users to verify their age, but many offer free and unrestricted access to any visitors to the site. Earlier this year, in a victory for a campaign by the Daily Mail, the Prime Minister announced an opt-in system under which households would be denied explicit online material unless they specifically asked for access. The new proposals follow a concerted campaign for an automatic block of porn by the newspaper and will be welcomed by campaigners on children internet safety. Some websites do require users to verify their age but a worrying number still allow unrestricted access to explicit material to all visitors It is hoped this latest development of a voluntary deal with credit card firms will tackle sites that let children see explicit images. Credit card companies already monitor illegal pornographic websites and liase with the authorities. But this would be the first time they have agreed to punish sites that do nothing to keep their pornographic images away from under-age children. Government sources have also made it clear that ministers would be prepared to consider legislation if necessary. The Authority for Television on Demand (Atvod), which regulates UK websites hosting videos, has drawn up plans to act against sites operating in this way. Playboy has already been fined for published explicit videos which could be seen by under-18s. Damian Green, the minister for policing and criminal justice, said: "The Government supports the work that Atvod has undertaken. This will explore with UK financial institutions and card companies the possibility of declining to process payments to websites operating outside the European Union which allow under-18s in the UK to view explicit pornographic content. Pete Johnson, chief executive of Atvod, said "outright blocking; of all websites that provide free hard-core pornography would not be "appropriate" because "this is material which is lawful for adults to view."