It was not exactly the modern-day equivalent of Martin Luther’s 95 theses, but a letter posted on the wall of the Vatican press office excoriating a journalist for publishing a leaked papal letter has created a stir nonetheless.

Father Federico Lombardi, Vatican head of communications, criticised Sandro Magister of L’Espresso magazine for publishing a draft of Pope Francis’s highly anticipated encyclical on the environment.

Lombardi wrote that the story released three days before a planned rollout of the nearly 200-page statement was an “obviously inappropriate initiative” that had been a source of major inconvenience for other journalists and caused serious disruption.

He added: “I therefore inform you [Magister] that your accreditation to this press office has been suspended from tomorrow indefinitely.”

Sandro Magister of @espressonline loses his @HolySeePress credentials for disclosing embargoed draft of Encyclical. pic.twitter.com/CAe3OGZRdW — Fr. Manuel Dorantes (@TweetingPriest) June 16, 2015

The leak of the draft document on Monday afternoon sent journalists in Rome into a frenzy, disrupting the elaborate plans of many news organisations on how they would cover the papal statement – the first of its kind. Some media outlets hesitated to report details of the draft after an email from Lombardi explicitly stated that doing so would be a breach of professional practices.

One correspondent, the National Catholic Reporter’s Joshua McElwee, aired his frustration and reluctance to publish a story about the leaked draft on Twitter on Monday night. By Tuesday, he was tweeting about how “another screaming match” had broken out within the press corp, where there was intense disagreement over how the leak should have been handled.

...And we've broken out into another screaming match @HolySeePress on ethics of writing on leaked encyclical. — Joshua McElwee (@joshjmac) June 16, 2015

While the church has been infused with high drama for 2,000 years, the leak has horrified the Vatican, with one official calling it an act of sabotage against the popular Argentinian pontiff. L’Espresso’s publication has also spurred a flurry of anxious questions as to who leaked it, and why?

The intrigue has been deepened by the fact that Vatican insiders consider the journalist at the heart of the controversy a conservative critic of Pope Francis and his reform agenda.

“He is more of a traditionalist,” one Vatican official said of Magister. “He loved Benedict and is very, very critical of Francis … he has got an agenda.”

“I don’t think this is about the issue of climate change. It is about change in the church – it is about the dynamism, about the way of looking at reality and calling it reality. It is about not having a judging church, which threatens some people.”

Austen Ivereigh, a biographer of the pope, said: “The pope and his close collaborators will be horrified by this leak. It is hard to know what the intention behind it was: to damage Francis, or for money, or both.”

Magister distanced himself from the situation, saying it had little to do with him. “To be honest, it’s not me that got the text, but the editor of L’Espresso, who informed me about it after he decided to put it online,” he said in an email exchange with the Guardian on Monday night.

He said he had merely added a few sentences of introduction to the text, which included his byline. “I have not the faintest idea … why the text was passed on to the editor of L’Espresso. I think it was random. There are dozens of copies of the encyclical that have been floating around over the last few days. This was bound to happen,” he wrote.

John Allen, a close follower of the Vatican and associate editor of the Crux, agreed that leaks of Vatican documents are quite common in the Italian press.

“In some ways, I’m surprised it took this long,” he said in an email. “Some have suspected an effort to sabotage the encyclical, but it’s hard to see how an advance look at what everyone already knew the pontiff was going to say accomplishes that. I’d read it instead as par for the course – whenever there’s a document coming out that’s generating intense interest, somebody’s going to try to get an early peek, attracting a massive online audience in the process.”

But another media outlet, Italian newspaper La Stampa, seemed to have no doubt that it was an act meant to hurt Francis. It said the leak had served two purposes: to weaken the message of the encyclical, which La Stampa said was “harshly critical” of the environmental policies of some superpowers, and to hurt efforts by the pope to change the church from within.

From the Vatican’s perspective, it was just the last in a long line of embarrassing press leaks. Earlier this year, L’Espresso also published the internal meeting minutes and expenses of Cardinal George Pell, which showed that the Vatican’s economics minister had spent about €500,000 (£360,000) setting up the church’s new economic ministry.

In 2012, Pope Benedict’s butler, Paolo Gabriele, was arrested after Vatican investigators found documents – including some that belonged to the pope – in his flat. Gabriele is believed to have leaked documents to investigative journalists, possibly to undermine efforts by the Vatican to become more financially transparent, though his alleged motives were not clear.