Labour's Harriet Harman has hit out at the government's decision not to force internet service providers (ISPs) to automatically block online pornography.
Writing in the Daily Mail, Harman said the move amounts to a "broken promise" after David Cameron campaigned for election on a pledge to be "the most family friendly government we’ve ever had in this country".
But her opposition was branded "sad, cynical and wrong" by Claire Perry, the conservative MP who led the campaign accused Harman of playing politics on a cross party issue.
Perry had gathered a petition with over 115,000 signatures that called for an automatic block on online pornography meaning users would have to request access from their ISP.
A ten week consultation on the issue found the move was not widely supported with only 35 percent wanting the automatic bar.
It also found there was a danger parents would be lulled into a false sense of security as an automatic bar could not guarantee it would filter all harmful content.
It also could not "deal with harms such as bullying, personal abuse, grooming or sexual exploitation which arise from the behaviour of other internet users".
Perry told BBC Wiltshire on Sunday that she was "obviously disappointed that the opt-in option has been rejected".
She added: "Clearly that was not the preferred choice of the 3,500 people who responded to the consultation and we have to base policy on what's been received not what we want."
Perry added that the report did indicate a "sea change in attitude" in how the topic was viewed by ISPs.
Ministers will now work with industry, charities and experts in relevant fields to see how to move forward on the issue.