PR expert testifies at Vatican fraud trial

The Vatican's big financial fraud and corruption trial has taken a soap opera turn with court-ordered testimony from a public relations specialist who has long harboured a grudge against one of the prime defendants, Cardinal Angelo Becciu.

Francesca Chaouqui was called to answer questions after text messages entered into the court record indicated she helped coach Becciu's key accuser into turning on the cardinal.

Chaouqui has never hidden her fantasy of taking revenge on Becciu, who she accused of being behind her 2015-2016 prosecution for passing confidential documents to journalists.

She apparently found the chance to settle scores when Vatican police in 2019 began investigating the secretariat of state's 350 million euro ($A545 million) investment in a London property.

Prosecutors charged 10 people, including Becciu, with a host of financial crimes, alleging Vatican monsignors and external brokers fleeced the Holy See of tens of millions of euros in fees and commissions.

Becciu is accused in two deals that are tangential to the London case and emerged after his one-time deputy, Archbishop Alberto Perlasca, flipped and started co-operating with prosecutors in August 2020.

Perlasca revealed last month that he changed his story after a friend started passing advice to him from someone she identified as a "retired magistrate".

The "retired magistrate" turned out to be none other than Chaouqui, who previously served on a papal commission tasked with investigating the Vatican's vast and murky finances.

She is known in Vatican circles for her role in the "Vatileaks" scandal, in which she was convicted of conspiring to leak confidential Vatican documents to journalists and received a 10-month suspended sentence.

Speaking to journalists outside the Vatican gates on Friday, Chaouqui promised to reveal that Becciu had betrayed Pope Francis and that the "transparency" she sought starting with her time on the commission was finally bearing fruit.

Bearing a box full of documents, Chaouqui denied she had misrepresented herself as a magistrate and insisted she was acting exclusively in the interest of Pope Francis and the truth.

"I'm going to explain to the Vatican tribunal and the world how the Holy Father was defrauded," she tweeted.