A once-powerful cardinal and nine other people are to learn their fate on Saturday when a Vatican tribunal hands down verdicts in a complicated financial trial that has aired the tiny city state’s dirty laundry and tested its justice system.

Judge Giuseppe Pignatone will read out the verdicts of the three-judge panel in the converted courtroom in the Vatican Museums, where prosecutors and defence attorneys have sparred for two-and-a-half years over the details of a money-losing investment in a luxury London property.

Cardinal Angelo Becciu, the first-ever cardinal to be prosecuted in the Vatican’s criminal court, is accused of embezzlement-related charges in two tangents of the London deal and faces up to seven years in prison if convicted. He has denied any wrongdoing.

Unlike most defendants, Becciu attended nearly all of the 86 hearings, saying Pope Francis clearly wanted him to face court judgment after Francis himself forced his resignation and removed his privileges as a cardinal before he was even charged.

The trial has raised questions about the rule of law in the city state and Francis’s power as absolute monarch, given that he wields supreme legislative, executive and judicial authority and has exercised it in ways the defence says jeopardised a fair trial.

The defence attorneys, while praising Pignatone’s even-handedness and saying they were able to present their arguments, lamented the Vatican’s outdated procedural norms that give prosecutors enormous leeway to withhold evidence and otherwise pursue their investigation nearly unimpeded.

In addition to Becciu, prosecutors charged nine others with a host of alleged financial crimes stemming from the secretariat of state’s 350 million euro investment in developing a former Harrod’s warehouse into luxury apartments.

Prosecutors allege Vatican monsignors and brokers fleeced the Holy See of tens of millions of euros in fees and commissions and then extorted the Holy See for 15 million euros (£13 million) to cede control of the building.

Prosecutors are seeking convictions for nearly 50 different charges of fraud, embezzlement, money-laundering, corruption, abuse of office and extortion.

They are seeking prison terms from three to 13 years and damages of over 400 million euros (£344 million) to try to recover the estimated 200 million euros (£172 million) they say the Holy See lost in the bad deals.

Becciu was once one of Francis’ top advisers and himself considered a papal contender.