A regional daily’s investigation into prisoners’ use of Facebook and mobiles led to them receiving extra time in jail after ministers intervened, it has been revealed.

North West Evening Mail reporter Will Metcalfe’s expose revealed that seven prisoners at its local jail, HMP Haverigg, had been pictured in images posted on Facebook.

Now the paper has published the results of a Freedom of Information request into its investigation which showed that government ministers demanded action after the story was published last October.

As a result, some of the prisoners involved had their sentences extended and guidance was issued to all prisons to advise governors on protocol.

Information released in the documents showed six more arrests were made and a further three Facebook profile pages were deleted as a result of the paper’s article, and the fact that none of the inmates pictured on Facebook in the Evening Mail’s story had been punished until ministers demanded action.

The paper also discovered that that the Ministry of Justice press advisors ‘strongly advised’ the prison governor to ignore phone calls from the title about it.

Evening Mail deputy editor James Higgins said: “We knew at the time that we had uncovered a serious flaw in the prison system.

“There was no way individuals serving time for serious crimes should have been able to post pictures to social media using mobile phones.

“The response we received from the prison and the MoJ at the time was frosty – but the documents we now have highlight the level of seriousness they attached to our discoveries.”

Documents released to the paper found that Jeremy Wright, under secretary of state for justice, was left fuming over the story when he was told no action had been taken because prison chiefs could not guarantee the prisoners pictured had been responsible for posting the pictures on Facebook.

It also revealed that guidance was issued to all prisons in the wake of the paper’s story, to advise governors on protocol.

Michael Spurr, NOMS chief executive, sent a bulletin to the UK’s 137 prison governors informing them not only was the person who uploaded the image committing an offence but anyone posing in photographs was also in the firing line.

Prison service guidelines also state offences must be punished within 48 hours of discovery unless in exceptional circumstances – but the prison had been aware of them for around three weeks when the secretary of state pushed for action.

The bulletin said: “There is significant and legitimate public concern about picture of serving prisoners appearing on social networking sites.

“Such pictures are likely to have been taken using unauthorised articles such as mobile phones which pose a serious risk to prison security.

“Failure to take robust action in response to such matters would undermine the confidence of victims, and the public in general, in the prison system and may weaken wider prison security policy/strategies in relation to the possession of illicit items.”