Children's campaigners and church groups have denounced Liberal Democrat calls for change in the law to allow 16-year-olds to view pornography.
The Lib Dems believe present laws on porn are nonsense
A majority of delegates at the party's spring conference in Southport on Saturday approved calls for laws on pornography to be relaxed.
They voted in favour of allowing 16 and 17-year-olds to visit sex shops, which would be made easier to set up and run.
But the NSPCC, the Church of England and the Tories all attacked the plans.
A spokeswoman for the NSPCC said: "We believe that this is a step in the wrong direction."
Angela Perkins, of the National Board of Catholic Women, said she was "speechless" at the news.
She said: "For a political party to say we think 16 is actually an adequate age to release children on to pornography is irresponsible.
"It's going backwards to the 18th Century.
"Sex is the only diet we are giving our children - this is almost like saying, 'That's fine, anything goes'."
A Church of England spokesman said it was opposed to all pornography because of the issue of exploitation.
"It is irrelevant whether you can appear in it at 16 or 116," he said.
"If it were to reduce protection, particularly for the most vulnerable, that would be regrettable."
Conservative Party co-chairman Dr Liam Fox also criticised the move.
He said: "This irresponsible policy is likely to lead to the exploitation of young people.
"With all the problems facing Britain, the Liberal Democrats have once again chosen to focus on the absurd and the obscure."
Lib Dem culture spokesman Don Foster had championed the softer line on porn.
He said 16- and 17-year-olds were "living in a twilight zone between childhood and adulthood", saying they were old enough to have sex and babies but could not watch explicit material.