It is known throughout the Vatican as the Relatio (Narration). It is contained in two stiff, unmarked red folders and runs to around 300 pages. Lying in a safe in the papal apartments of the Apostolic Palace overlooking St Peter's Square, it will be at the forefront of the minds of the 115 cardinals who on Tuesday are to file into the Sistine chapel to start the conclave that elects the next pope.

In the Relatio are the findings of three cardinal-detectives, appointed last year by ex-pope Benedict XVI to investigate the leaking of documents from his study. The cardinals, headed by a Spanish member of the Opus Dei fellowship, Cardinal Julián Herranz, discovered the main source of the leaks – the pope's butler, Paolo Gabriele.

But they found a great deal else – and some of it is reportedly extremely compromising. According to one unconfirmed report, they stumbled on a gay sex ring in the Vatican, some of whose members had been blackmailed.