Pornography produced by consenting adults engaging in legal acts will no longer be prosecuted under Britain’s historic obscenity laws, the Crown Prosecution Service has said.

The Obscene Publications Act dates back to 1959 and is designed to protect the public from material that could “deprave and corrupt” their minds. The law was famously invoked in the unsuccessful prosecution of DH Lawrence’s novel Lady Chatterley’s Lover but in recent years has been largely used in cases involving pornography.

However, juries have increasingly taken a liberal view on whether material is likely to corrupt the minds of the British public, making it difficult for the authorities to achieve a successful prosecution. In 2012 a jury cleared “Sleazy” Michael Peacock after a landmark case during which the court watched hours of DVDs featuring consensual male fisting, urination and BDSM activities before concluding they did not find it obscene.

A CPS spokesperson confirmed the change, which followed a public consultation: “It is not for the CPS to decide what is considered good taste or objectionable. We do not propose to bring charges based on material that depicts consensual and legal activity between adults, where no serious harm is caused and the likely audience is over the age of 18.

“The CPS will, however, continue to robustly apply the law to anything which crosses the line into criminal conduct and serious harm.”

Myles Jackman, a solicitor who specialises in obscenity cases and has campaigned for the law to be changed, welcomed the announcement. “In free speech and privacy terms, these changes represent the most significant public changes of attitude by an institution of the state towards consensual adult sexual content since the Wolfenden report in 1957,” he said.

“In principle, anything which is legal to consent to doing is now legal to consent to distribute images of, providing the likely audience is over the age of 18. The law has finally caught up with social standards.”

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The new guidelines also make it clear that material that is purposefully obscene can be justified as in the public good if it is “in the interests of science, literature, art or learning”. The Obscene Publications Act will remain on the statute books, alongside separate legislation specifically relating to extreme pornography which has been used in cases such as that involving a former IRA informant nicknamed “Stakeknife”.

The treatment of pornography and adult material is at the forefront of a growing debate over broader issues of media regulation and attempts to filter the internet by tech businesses and national governments.

Many major social media sites such as Tumblr, which were once home to substantial amounts of adult material, are restricting or removing adult content completely as they struggle to ensure the material is not seen by under-18s and make sure their service is not inadvertently used to hold images of child abuse.

The UK is due to introduce strict rules on the online distribution of legal pornography from April, which will require the public to register and go through an age-check process to view sites that are currently unfiltered.