Members of the Order of Malta have been warned not to defend the Dictator Pope book or its author on social media, or make statements “offensive to the Holy Father”, the Catholic Herald reports.

In an email seen by the Catholic Herald, members are warned that they face disciplinary action if they fail to comply, referring to Articles 119 to 125 of the Code of the Order. These articles state that members can face sanctions ranging from warnings to expulsion if they act in an unworthy manner.

It also tells members to “swiftly” report anyone not complying.

The email, which was sent to British members on Holy Saturday, states that the President of the British Association has asked that the message be circulated to all members “especially those who use social media”.

A spokesperson said the email was sent to all Order of Malta members worldwide, the Herald reports.

The Order suspended Henry Sire last month after he was revealed as the author of the Dictator Pope, a book that caused a considerable stir when it appeared in December. The book tells the story of Francis’s pontificate, as well as his life before becoming Pope, comparing his style of governance with that of Argentine dictator Juan Perón.

The Order of Malta described the book as a “vile attack” on the Pontiff, and said it was launching an investigation into Sire.

Henry Sire has hinted that he will challenge the suspension.