Pope Benedict's place in papal history will depend on how he deals with paedophile clerics, a new biography of the German Pontiff claims.

The book, Pope Benedict XVI The First Five Years, is written by Irish priest Fr Michael Collins, an expert in Vatican affairs.

“As the pontificate continued, the unfolding issue of clerical child abuse and its management by religious superiors, bishops and the Holy See occupied more and more of Benedict's energy,” writes Fr Collins. “His leadership was reactive, not pro-active.”

Fr Collins, a priest of the archdiocese of Dublin, taught in Rome until 2005. He was the first to publish an English-language biography soon after the election of Cardinal Joseph Ratzinger.